Reaper transfigure gem bug(?) interaction

While having two reaper of revenants and a reaper of eviserating (This is possible by summoning the three reaper of revenants first, then summon the reaper of eviserating). Activating reaper of eviserating will re-summon the reaper of eviserating and killing the other two reaper of revenants one by on, instead of performing the ultimate attack

*Small extra finding. Using Reaper of revenant (ROR) and Reaper of Eviserating (ROI) in a specific order enable the use of the reaper's on-command slash ultimate attack.
First you need to summon two ROR and one ROI. Resummon the two ROR again by using the spell twice. The on-command slash atk of ROI should be usable afterward. However, the activation will now has a cooldown (kinda like normal summon reaper)

Not sure if you found this, but while testing it seems Reaper of eviscerating actually doesn't go on cooldown alongside 2 revenants when I test in the aqueduct, but does in hideout.

2 revenants > summon eviscerating > summon 2 revenants > spam slash dash

Upon further testing, I slotted normal reaper, did the same order, and had a cooldown, then slotted eviscerating reaper, repeated the order and had a cooldown. I then went to a new zone, not re-summoning anything and had no cooldown. So definitely something going on in the background