I was going to let this one go. But, I thought I should bring it up in case someone else might be experiencing this issue. And, I may end up using this feature after all. Sorry to bring up another issue. I know how annoying it can be.
Note: The initial spawn works just fine.
When a spawner is set to respawn and respawn random is checked and the groups are multi-monster groups, when the respawn happens it could spawn more than 1 spawn.
Example, I have a spawn set to respawn and choose random group. Each group that could spawn is made up of 2 or more monsters, when the re-spawn happens, I could end up with 2 or more spawned at that location. Spawn All Members is NOT checked. It seems to work just fine if the groups are made up of single monsters.
Note: Battle is set for TURN BASED combat if that makes much of a difference. I hope this made sense.