I upgraded from 5th to 7th gen.
Experienced very frequent Safari web page refreshes (“a problem has occurred and...”). This was happening only on certain websites that update a large amount of data more or less continuously (example golf tournament leaderboards). Happened even with only 2 safari tabs open (and no other apps running). Clearing Safari history or restarting iPad stopped it only temporarily (20-30 minutes), then it would start doing it again.
This was happending on both iOS 12 and 13.
The problem totally went away with Gen 7 iPad. I attribute that likely to RAM increase from 2 to 3GB. Re A9 to A10, Gen 7 seems a tiny bit snappier, but is hard to tell really.