Change 804757 had a related patch set uploaded (by Esanders; author: Esanders):

[mediawiki/extensions/DiscussionTools@master] ReplyWidgetVisual: Overwite ve.init.platform.sessionStorage with memory-wrapped store

https://gerrit.wikimedia.org/r/804757

Change 804757 merged by jenkins-bot:

[mediawiki/extensions/DiscussionTools@master] ReplyWidgetVisual: Pass in memory-wrapped store to VE

https://gerrit.wikimedia.org/r/804757

This works as expected. See https://photos.app.goo.gl/9rdCkUeaHuuB4v6W6.

@matmarex , I somehow thought you were trying to reopen the ticket and decided to check it.

Here's what I found: https://photos.app.goo.gl/CPQXHazFbNTtZrS8A.
On click of the the "Show 7 new comments" button:

• Reply buttons change to [reply] link
• Reply tool is not displayed anywhere and the esc button doesn't help. It leaves the user confused about how to interact with the page

When I reload, the Reply links are disabled and the one I initially clicked is bold and throws an error when clicked. See

In T310438#8134935, @EAkinloose wrote:

@matmarex , I somehow thought you were trying to reopen the ticket and decided to check it.

Here's what I found: https://photos.app.goo.gl/CPQXHazFbNTtZrS8A.
On click of the the "Show 7 new comments" button:

• Reply buttons change to [reply] link
• Reply tool is not displayed anywhere and the esc button doesn't help. It leaves the user confused about how to interact with the page

When I reload, the Reply links are disabled and the one I initially clicked is bold and throws an error when clicked. See F35402184

Sorry it took me so long to get back to this. These issues don't seem to be related to the changes in this task.

Considering that the Reply buttons changed to [reply] links, I suspect that the issues you ran into were related to the rollout of that feature (T255560) – specifically, it looks like when you viewed the page, you got the new buttons while viewing the (uncached) old revision, and then old links while loading the (cached) new revision. I'm not sure why the exceptions occurred in this scenario, but I don't think it's worth investigating now, when the old cached data is gone.

It looks like the errors were real and some users were actually affected by them (although very few). They seem to have stopped occurring now, so either we fixed them in another patch, or they were fixed by the old caches expiring.

Moving back to sign-off per the original QA review (T310438#8024666).