I do not use Galaxy, nor do I plan to. While looking in the "What did just update?" thread, I saw some games were updated, yet they did not get the update tag in my library. Refresh did not work either.

Does anyone have any other suggestions?

GOG's game update flag is known to broken for years.

The only reliable way to update everything you have, is to use 3rd party tools for now.
Even GOG Galaxy itself is not that reliable.

We've been recently discussing the matter here:

https://www.gog.com/forum/general/can_we_have_the_blue_dot_for_game_updates_back_please

I see the blue dot on an updated game when I first visit the page. I saw it yesterday on "I have no mouth..." A simple refresh and it goes away.