Okay. I've looked at the code and can see an obvious problem. You're right Bowl - it's always been a problem.
It happens if you're quick and your network is a little sluggish. This explains why Bowl might see it when adding lots of rolls before filling them in. Users with slow networks will see this more often too. I guess tables exacerbate this because adding rolls is now much faster.
The system sends a message to the server asking for a new roll, passing the number of rolls it already has. The system returns the empty roll THEN it updates the number of rolls. The problem is underlined.
CLICK. Hey server, gimme a roll. I have 0 at the moment.
CLICK. Hey server, gimme a roll. I have 0 at the moment.
REPLY. Here you go - here's your first roll. Roll count is now 1.
REPLY. Here you go - here's your
first roll. Roll count is now 2.
I've repro'd this by hammering on the Add basic roll button.
See how it thinks it has two roll 2s, then skipped 3?