I’ve noticed that the generation of ALT Text for photos that I upload is taking longer than it did. Typically the text was generated in a few minutes, 5 -10 minutes at longest. Now it appears to take much, much longer - how long I am not sure as I have gone back to writing my own text.
I noticed this the other day too, and think it was because of high load on our servers after rolling out the new link preview cards. But I did a quick test just now and the text was generated quickly, in about 15 seconds.
I’ll investigate some more and see if we can ensure this won’t get bogged down again.