When casting regroup, often, but not always, the spell continues to cast, leading to a chain of casts where PCs continue to get teleported around. Multiple castings do not subtract castings from the available spell slots. Moving does not always interrupt the runaway chain, like it usually does for other spells.
The number of chaining effects is not consistent; sometimes two, sometimes 8+ it seems to be somewhat correlated to the number of PCs around -- when using it on just a familiar for example, I see the behavior less often, and with fewer castings in the chain.
Haha... I always thought the pcs were doing that intentionally, showing off the joy of being able to teleport people around with a lvl 1 spell.
This wasn't being done intentionally?
Fix attempted. Report results.
Tested several times since. No recurrence of the bug. I think it's fixed!