Board Thread:Support Requests - Community Management/@comment-36737086-20190225195113/@comment-1038387-20190225200834

It's not the welcome message the OP is concerned about, it's the red link in it.

If you've got edit section and right-click edit section turned on in your Preferences, you should be able to bypass any archive lock that way. AutoWikiBrowser can also edit archived talk pages.