@beanbag Well, I don’t know a lot about this but it sounds like the data is probably being stored in cache if clearing individual cookies doesn’t work but clearing everything for all time in browser data does. Linking info on how to view and delete a cache file for a site. Can try that next go around.
I think you need to download a cache file viewer tool to actually see the contents of the cached file. Maybe a community member with some actual hands-on knowledge and experience will pop in and help. I’m just repeating info I’ve found from a web search.
Sorry I can’t be of more help. Please post an update. Take care. 