TL;DR:
Lightning Spear and the Damage Field created by Okun (Ball Lightning) can snapshot Overpower. It happened with me in one separate occasion for each. Other people have said that Lighting Spear snapshots when the very first skill used Overpowers.
A few days ago I was in a Nightmare Dungeon and notice many Overpower damage numbers against every enemy group. I remembered that, in season 7, it was possible to snapshot Overpower with Lightning Spear (LS) and after a few tests I confirmed that LS was Overpowering on every hit.
I let all LS disappear a couple of times, but the snapshot persisted.
Later in the Sorcerer forum other players told me that this happens when the very first LS that you use Overpowers.
This seemed to be a known issue, so I didn’t see need to report the bug.
Well, yesterday the same thing happened with the Damage Field generated by Okun’s Catalyst with Ball Lightning (BL). I let all BL disappear on purpose 3 times (probably more while testing) and only on the third try the snapshot stopped.
Before this last attempt I removed Axial Conduit and re-equiped during tests.
Obs: I’m playing on the Eternal Realm.