5.8.1 WP update creates Astra issue

Updating to 5.8.1 caused an immediate slowdown in page loading (from 0.9 seconds to 3.8 seconds). I cleared caches and got the same result. Using Gtmetrix data, I was able to determine that after the update, the site looks for the wrong theme css file, and loading freezes until it decides it’s not there. I’m also notifying the makers of the theme (Astra/Astra Pro). I’m posting here because it wasn’t an Astra update the caused the problem, so I’m not really sure if the possible fix lies with the theme. Reverting to 5.8.0 ended the problem immediately, which makes me think it must be connected to the WP update (and might therefore have implications for other themes).

Since I’ve reverted, the link above isn’t actually going to be very helpful.

I don’t know if this is helpful either, but the correct css file is astra-addon-61321f8e8b8846-78597017.css. The file the site looks for after the update is stra-addon-61129f2e3121d1-79533973.css and references an earlier version (3.5.8) Current Astra version is 3.6.9, Pro plugin is 3.5.9.

I know this is an odd issue. Any help will be greatly appreciated.

The page I need help with: [log in to see the link]