Vlad
I don't think it was an indexing problem, I let the program be open for maybe 30 minutes, and when not active it would cool down. As soon as switching to Orion it would start blasting the fans and spamming this "automatic index on icon_info(HASH)" message.
I've now reimported my bookmarks and reading list without any issue, in total a few hundred items. My history is about 20 000 items, could that be the source of any problems?
Edit: About 10-15 minutes after reimporting my bookmarks, Orion has started to consume huge amounts of CPU . I deleted caches in the developer menu, it didn't change anything.