The (thanks) link still appears next to an edit that has been oversighted or otherwise suppressed. Clicking the link gives the confirmation as normal and clicking OK appears to send the thanks as normal (I'm waiting for confirmation of whether the thanks is received - I don't have access to oversight to test on one of my own edits).
Suppression of an edit should also suppress the ability to thank someone for that edit.
I spotted this bug at https://en.wikipedia.org/w/index.php?title=Wikipedia:Arbitration/Requests/Case/Manning_naming_dispute/Workshop&action=history where the edits from 00:26 to 02:37 on 13 September have been removed.
Version: unspecified
Severity: normal