Optimizer lot size change bug

I've run an issue with several different bots of different codebases where if I'm using the optimizer and it finishes or I stop it manually, and then I change the lot size and attempt to run it again the optimizer will act like it's starting up but then after a few seconds it will stop and the "play" arrow will reenable.  This happens when the lots are set via a parameter, and even happens when the lot size is calculated if one of the parameters the calculation is based on is changed.  The only resolution seems to be to restart calgo at that point as it won't actually run the optimizer anymore until it is restarted.  

This has happened to with multiple bots on different computers so while it seems like an odd bug, it seems to be one that's repeatable.