Safari WebExtensions (MV3): Content Script context persists across navigation, causing message routing to wrong (zombie?) pages

Summary:

Content scripts injected via manifest continue to receive and respond to chrome.tabs.sendMessage() calls even after the user has navigated away from the original page, causing messages intended for the current tab to be handled by zombie contexts from previous pages.

Environment:

• Safari/iOS Version: 18.5
• Extension Manifest: Version 3

Expected Behavior:

When a user navigates from Page A to Page B: Page A's content script context should be destroyed. chrome.tabs.sendMessage(currentTabId, message) should only reach Page B's content script Only Page B should be able to respond to action button clicks (or other background to content messages).

Actual Behavior:

When navigating from Page A to Page B: Page A's content script context persists as a "zombie". chrome.tabs.sendMessage(currentTabId, message) reaches zombie context instead of the Page B's one. Hence, it looks like the extension is broken because the content script does not respond to the background messages.

Details:

• Tab ids are properly recognized by both background and content script
• The problem does not always occur; it occurs on random occasions. It's quite easy to have it reproduced.
• It can be reproduced easier if user clicks ext icon during site loading (before it fully loaded), triggering ActionClick (ext icon click) event and then sending a msg upon it to the content script
• Regardless of whether the content script is injected into the tab using manifest.json, registerContentScripts, or executeScript, the problem is still there
• Once the problem occurs, e.g. user is on macys.com but zombie injected content script believes it's google.com (a previous page), even refreshing the tab doesnt change anything - zombie context is still there (thinking it's still google.com) . Changing a domain to something completely different one could help though. Then going back to macys.com could still lead to the described issue.
• A zombie content script does not have access to the page's console function and others.

Example communication

• Sending following message from the background to the content script using chrome.tabs.sendMessage()

{
  "tab": {
    "id": 155,
    "active": true,
    "url": "https://www.macys.com/",
    "title": "Macys.com"
  }
}

• Results in the content-script zombie context response (the url is taken from the window.location.href)

  "message": {
    "type": "ActionClicked",
    "data": {}
  },
  "response": {
    "data": {
      "windowUrl": "https://www.google.com/",
      "contentReached": true,
      "timestamp": "1,753,138,945,272",
    }
  }
}