The topic about the release of discourse 3.2 says
The fix, which was mentioned in the second post, will be included there. But there was a report that this fix did not help here.
The issue @JammyDodger described, which is related to the reactions plugin, is not fixed. But with this issue you cannot highlight text at all, so it is different from your issue.
So all in all the issue was fixed for some sites. Even if there is another fix, you won’t know whether your bug was fixed untill december, because you at the stable branch you only get security fixes between releases. That’s the advantage of tests-passed you can update directly after a fix is there.