Change 658311 had a related patch set uploaded (by Bartosz Dziewoński; owner: Bartosz Dziewoński):
[mediawiki/extensions/DiscussionTools@master] Fix cookie loading hack

https://gerrit.wikimedia.org/r/658311

Change 658311 merged by jenkins-bot:
[mediawiki/extensions/DiscussionTools@master] Fix cookie loading hack

https://gerrit.wikimedia.org/r/658311

The patch appears to have fixed the issue for a short while, but it looks like it broke again - at least for me.

In T272850#6778945, @Blablubbs wrote:

The patch appears to have fixed the issue for a short while, but it looks like it broke again - at least for me.

We appreciate you letting us know. To confirm, is this the edit you made [i] where you re-enabled the script?

i. https://meta.wikimedia.org/w/index.php?title=User:Blablubbs/global.js&diff=prev&oldid=21007967

The patch is not deployed yet (it will be deployed next week, starting on 2021-02-02), so I have no idea what fixed your issue, but it wasn't it. :)

Indeed, that was the edit -- I had enabled enterprisey's reply-link for a while and just uncommented the line so I could just wait and see when it would start working again. Some time after uncommenting, it actually worked for a bit -- see e.g. the tags here https://en.wikipedia.org/w/index.php?title=User_talk:Blablubbs&diff=prev&oldid=1002953117. I'll keep you up to date in case it unbreaks again.

In T272850#6780107, @Blablubbs wrote:

Indeed, that was the edit -- I had enabled enterprisey's reply-link for a while and just uncommented the line so I could just wait and see when it would start working again. Some time after uncommenting, it actually worked for a bit -- see e.g. the tags here https://en.wikipedia.org/w/index.php?title=User_talk:Blablubbs&diff=prev&oldid=1002953117. I'll keep you up to date in case it unbreaks again.

Noted. Thank you for this context, @Blablubbs.

Per T272850#6779752, I'm going to wait to close this until @Blablubbs verifies the script is working as expected some time after 2021-02-02.

Will do @ppelberg; thanks for the quick response!

Update: Now started working again.

Update 2: Has since dropped in and out a couple times, but has been functioning consistently today -- I assume the fix was pushed and is working. @ppelberg Thanks for fixing this so quickly, I think the issue can be closed.

Well, sorry for the spam but it's broken again. I'll just report back once it's been working consistently for a couple days.

In T272850#6799631, @Blablubbs wrote:

Well, sorry for the spam but it's broken again. I'll just report back once it's been working consistently for a couple days.

Thank you for letting us know, @Blablubbs – we're going to re-investigate this next week, once 1.36.0-wmf.29 arrives on all wikis.

@Blablubbs, okay! Now that wmf.30 has landed on all Wikipedias, can you please let us know whether the Reply Tool is available and working as you expect it to?

@ppelberg I've given it a couple days to see that it's working reliably, and indeed it is. I think this can be closed -- thanks for the fix :).