Toggling lists too quickly causes errors

[u-RraaLL]

Prerequisites

• I verified that this is not a filter list issue. Report any issues with filter lists or broken website functionality by using the chat icon in the popup panel.
• This is NOT a YouTube, Facebook or Twitch report. These sites MUST be reported by clicking their respective links.
• This is not a support issue or a question. For support, questions, or help, visit /r/uBlockOrigin.
• I performed a cursory search of the issue tracker to avoid opening a duplicate issue.
• The issue is not present after disabling uBO Lite in the browser.

I tried to reproduce the issue when...

• uBO Lite is the only extension.
• using a new, unmodified browser profile.

Description

After Firefox finally approved queued releases I wanted to test Resetting to defaults. My first try actually failed, the page refreshed, there was no spinner icon and no changes took place. Then I tested a few more times and there were no issues. So this is just a side note.

Anyway, after resetting to defaults, I went to disable filter lists to not conflict with uBO, and this error came up and some of the lists got re-selected.

Error: Type error for parameter options (Error processing addRules.24.condition.requestDomains.169: Error: Invalid domain 185.164.59.38.12) for declarativeNetRequest.updateSessionRules.

A specific URL where the issue occurs.

uBOL Dashboard > Filter lists

Steps to Reproduce

1. Open uBOL Dashboard > Filter lists.
2. Start quickly disabling filter lists from top to bottom.
3. If nothing happens, quickly select lists , then try deselecting again.

Should be easily reproducible. It is on my side. Even with just two sequential lists. Mostly with deselecting, but sometimes also with selecting lists.

It doesn't seem to happen if I wait ~1s before next (de/)selection. But I don't remember encountering this issue on previous versions.

Expected behavior

There should be no errors.

Actual behavior

Error interrupts changing lists.

uBO Lite version

2026.111.1925

Browser name and version

Firefox 145

Operating system and version

Linux

[teor2345]

I've also seen this with versions 2026.308.1810 and 2026.301.2014 on Safari on iOS 18.7.3.

[gorhill]

What's the error? Are you talking about

Error: Type error for parameter options (Error processing addRules.24.condition.requestDomains.169: Error: Invalid domain 185.164.59.38.12) for declarativeNetRequest.updateSessionRules.

?

[teor2345]

I'm sorry, I don't have a screenshot of the exact error. If it comes up again, I'll let you know.

And I'm reluctant to do further testing, because it took me about 2 weeks to get the extension to activate permanently in Safari. Every few days it was being disabled and reset to default settings, without me doing anything to any extension or Safari settings. (I have no idea what I did to make it stick, except maybe closing a bunch of open tabs. Just turning it back on and re-loading my saved ruleset settings eventually worked.)