Change #1184708 had a related patch set uploaded (by Aklapper; author: Aklapper):

[mediawiki/extensions/CentralAuth@master] Local accounts table: Wrap long blocklog entries to keep table width

https://gerrit.wikimedia.org/r/1184708

I was able to test @Aklapper's patch locally, and it appears to resolve the issue. See the before and after states below;

before	after

One additional comment, which could be addressed in a separate patch, is that if we're using links in the block reason, they should be hyperlinks (clickable); currently, they're just plain text. It can be copied and pasted, but it could use some improvements.

That block reason should probably have used a wikilink, which are supported on Special:CentralAuth (as well as Special:Log and other places where block reasons can be displayed).

Change #1184708 merged by jenkins-bot:

[mediawiki/extensions/CentralAuth@master] Special: Wrap long blocklog entries to keep table width

https://gerrit.wikimedia.org/r/1184708

Whilst it should have been a wikilink, admins are busy people and might not be bothered to do the conversion. We should account for these kind of cases.

In T403661#11149716, @Matrix wrote:

Whilst it should have been a wikilink, admins are busy people and might not be bothered to do the conversion. We should account for these kind of cases.

I think that's covered by T16892: Linkify plain external links in edit summaries, log comments, block reasons. Special:CentralAuth uses the same parser.