I was experimenting today with Wikipedia using my testing account Nadšený nováček. This user was granted confirmed rights manually by me as a Czech Wikipedia admin. Despite that, the Edit button sometimes said "Edit" and sometimes said "View source" - it seems that logic for determining permissions to edit that article doesn't seem to work reliably. See my recording at https://martin.urbanec.cz/files/screencasts/prague.webm. This recording was shooted today, 23 January 2020, at approximetly 9:30. This is about 12 hours after the account was granted confirmed rights.
For the records, "Zobrazit zdroj" means "View source" and "Editovat" means "Edit". I wasn't able to figure out any exact step to reproduce or anything.