How long can I let a yeast cake sit before reuse?

Well, given that I just loosened/unsealed one side of the lid, but didn’t remove it while transferring the beer to the keg hopefully means that there’s still a CO2 blanket on top of the yeast cake (from the original headspace) even though some regular air entered the fermenter to equalize the pressure of the bucket during transfer.  I’ll keep my fingers crossed and hope that I don’t see any reticulated patterns in the cake this weekend.