AGOL is very bad at handling geometry errors in fact it can completely prevent your hosted layer from working on multiple different avenues. What is desperately needed is to allow the check and repair geometry tools within ArcPro to run on the Hosted layers themselves of the runtime databases from downloading a map off line.
I recently had a ticket where a hosted feature layer had multiple geometry errors, the solution was to repair the geometry errors but you can't do this without deleting all of the data and reloading it or overwriting the service. AGOL can't deal with geometry errors but has has no means to prevent them from occurring within the service, no means to identify them in the service, and no means to repair them in the service.
