An Altium agent tool sized back drills the way Altium's help says (hole plus 2 times the oversize, giving 0.8 mm), while Altium's own Draftsman drill table and the board's hole list both say 0.5 mm (hole plus the oversize once).
From the Grok pain-radar digest, Oct 20 2026 (7:41 AM to 9:41 AM ET slots). Verified live 2026-10-21: issue/PR read on GitHub; title and state confirmed.