diff --git a/apps/browser/src/autofill/background/auto-submit-login.background.spec.ts b/apps/browser/src/autofill/background/auto-submit-login.background.spec.ts
index 82a907a9e43..01767281a20 100644
--- a/apps/browser/src/autofill/background/auto-submit-login.background.spec.ts
+++ b/apps/browser/src/autofill/background/auto-submit-login.background.spec.ts
@@ -249,6 +249,20 @@ describe("AutoSubmitLoginBackground", () => {
           false,
         );
       });
+
+      it("properly cleans up auto-submit workflows when requestInitiator is falsy but active auto-submit hosts exist", async () => {
+        webRequestDetails.initiator = undefined;
+        jest
+          .spyOn(BrowserApi, "getTab")
+          .mockResolvedValue(mock<chrome.tabs.Tab>({ url: validAutoSubmitUrl, id: 1 }));
+
+        triggerWebRequestOnBeforeRequestEvent(webRequestDetails);
+        await flushPromises();
+
+        expect(autoSubmitLoginBackground["validAutoSubmitHosts"].has(validAutoSubmitHost)).toBe(
+          false,
+        );
+      });
     });
 
     describe("when the extension is running on a Safari browser", () => {
diff --git a/apps/browser/src/autofill/background/auto-submit-login.background.ts b/apps/browser/src/autofill/background/auto-submit-login.background.ts
index f593fab2516..07f0b98318a 100644
--- a/apps/browser/src/autofill/background/auto-submit-login.background.ts
+++ b/apps/browser/src/autofill/background/auto-submit-login.background.ts
@@ -1,5 +1,3 @@
-// FIXME: Update this file to be type safe and remove this and next line
-// @ts-strict-ignore
 import { filter, firstValueFrom, of, switchMap } from "rxjs";
 
 import { PolicyService } from "@bitwarden/common/admin-console/abstractions/policy/policy.service.abstraction";
@@ -64,6 +62,7 @@ export class AutoSubmitLoginBackground implements AutoSubmitLoginBackgroundAbstr
           this.policyService.policiesByType$(PolicyType.AutomaticAppLogIn, userId),
         ),
         getFirstPolicy,
+        filter((policy): policy is Policy => policy !== undefined),
       )
       .subscribe(this.handleAutoSubmitLoginPolicySubscription.bind(this));
   }
@@ -165,7 +164,11 @@ export class AutoSubmitLoginBackground implements AutoSubmitLoginBackgroundAbstr
     details: chrome.webRequest.OnBeforeRequestDetails,
   ): undefined => {
     const requestInitiator = this.getRequestInitiator(details);
-    const isValidInitiator = this.isValidInitiator(requestInitiator);
+    if (!requestInitiator && this.validAutoSubmitHosts.size === 0) {
+      return;
+    }
+
+    const isValidInitiator = requestInitiator ? this.isValidInitiator(requestInitiator) : false;
 
     if (
       this.postRequestEncounteredAfterSubmission(details, isValidInitiator) ||
@@ -175,14 +178,20 @@ export class AutoSubmitLoginBackground implements AutoSubmitLoginBackgroundAbstr
       return;
     }
 
-    if (isValidInitiator && this.shouldRouteTriggerAutoSubmit(details, requestInitiator)) {
+    if (
+      requestInitiator &&
+      isValidInitiator &&
+      this.shouldRouteTriggerAutoSubmit(details, requestInitiator)
+    ) {
       this.setupAutoSubmitFlow(details);
       return;
     }
 
-    this.disableAutoSubmitFlow(requestInitiator, details).catch((error) =>
-      this.logService.error(error),
-    );
+    if (requestInitiator || this.validAutoSubmitHosts.size > 0) {
+      this.disableAutoSubmitFlow(requestInitiator || "", details).catch((error) =>
+        this.logService.error(error),
+      );
+    }
   };
 
   /**
@@ -368,8 +377,9 @@ export class AutoSubmitLoginBackground implements AutoSubmitLoginBackgroundAbstr
     }
 
     const tab = await BrowserApi.getTab(details.tabId);
-    if (this.isValidAutoSubmitHost(tab?.url)) {
-      this.removeUrlFromAutoSubmitHosts(tab.url);
+    const tabUrl = tab?.url;
+    if (tabUrl && this.isValidAutoSubmitHost(tabUrl)) {
+      this.removeUrlFromAutoSubmitHosts(tabUrl);
     }
   };
 
@@ -427,7 +437,7 @@ export class AutoSubmitLoginBackground implements AutoSubmitLoginBackgroundAbstr
    */
   private getUrlHost = (url: string) => {
     let parsedUrl = url;
-    if (!parsedUrl) {
+    if (!parsedUrl || typeof parsedUrl !== "string") {
       return "";
     }
 
@@ -495,6 +505,10 @@ export class AutoSubmitLoginBackground implements AutoSubmitLoginBackgroundAbstr
     message: AutoSubmitLoginMessage,
     sender: chrome.runtime.MessageSender,
   ) => {
+    if (sender.frameId == null || !sender.tab || !message.pageDetails) {
+      return;
+    }
+
     await this.autofillService.doAutoFillOnTab(
       [
         {
@@ -515,7 +529,9 @@ export class AutoSubmitLoginBackground implements AutoSubmitLoginBackgroundAbstr
    * @param sender - The message sender.
    */
   private handleMultiStepAutoSubmitLoginComplete = (sender: chrome.runtime.MessageSender) => {
-    this.removeUrlFromAutoSubmitHosts(sender.url);
+    if (sender.url) {
+      this.removeUrlFromAutoSubmitHosts(sender.url);
+    }
   };
 
   /**
@@ -526,7 +542,7 @@ export class AutoSubmitLoginBackground implements AutoSubmitLoginBackgroundAbstr
    */
   private async initSafari() {
     const currentTab = await BrowserApi.getTabFromCurrentWindow();
-    if (currentTab) {
+    if (currentTab?.url && currentTab.id != null && currentTab.id >= 0) {
       this.setMostRecentIdpHost(currentTab.url, currentTab.id);
     }
 
@@ -558,7 +574,7 @@ export class AutoSubmitLoginBackground implements AutoSubmitLoginBackgroundAbstr
     }
 
     const tab = await BrowserApi.getTab(activeInfo.tabId);
-    if (tab) {
+    if (tab?.url && tab.id != null && tab.id >= 0) {
       this.setMostRecentIdpHost(tab.url, tab.id);
     }
   };
@@ -570,7 +586,7 @@ export class AutoSubmitLoginBackground implements AutoSubmitLoginBackgroundAbstr
    * @param changeInfo - The change information of the tab.
    */
   private handleSafariTabOnUpdated = (tabId: number, changeInfo: chrome.tabs.OnUpdatedInfo) => {
-    if (changeInfo) {
+    if (changeInfo.url) {
       this.setMostRecentIdpHost(changeInfo.url, tabId);
     }
   };
@@ -626,13 +642,17 @@ export class AutoSubmitLoginBackground implements AutoSubmitLoginBackgroundAbstr
    * @param sender - The message sender.
    * @param sendResponse - The response callback.
    */
-  private handleExtensionMessage = async (
+  private handleExtensionMessage = (
     message: AutoSubmitLoginMessage,
     sender: chrome.runtime.MessageSender,
     sendResponse: (response?: any) => void,
   ) => {
     const { tab, url } = sender;
-    if (tab?.id !== this.currentAutoSubmitHostData.tabId || !this.isValidAutoSubmitHost(url)) {
+    if (
+      !url ||
+      tab?.id !== this.currentAutoSubmitHostData.tabId ||
+      !this.isValidAutoSubmitHost(url)
+    ) {
       return null;
     }
 
diff --git a/apps/browser/src/platform/browser/browser-api.ts b/apps/browser/src/platform/browser/browser-api.ts
index cfc39fa18a1..feefd527636 100644
--- a/apps/browser/src/platform/browser/browser-api.ts
+++ b/apps/browser/src/platform/browser/browser-api.ts
@@ -560,7 +560,8 @@ export class BrowserApi {
    * @param event - The event in which to remove the listener from.
    * @param callback - The callback you want removed from the event.
    */
-  static removeListener<T extends (...args: readonly unknown[]) => unknown>(
+  // Chrome's Event.removeListener expects callback args as `any[]` to align with its internal event typings.
+  static removeListener<T extends (...args: readonly any[]) => any>(
     event: chrome.events.Event<T>,
     callback: T,
   ) {