There is a fairly easily recreatable bug with command and extra movements
You can cause it to happen by giving a soldier who has both actions left a command - and then blue moving him somewhere - he gets another blue move after that because the extra action, but the reticle for where to go disappears
Pan around for a bit and it will usually crash the game
[1.4] Command move crash bug
Re: [1.4] Command move crash bug
This isn't related to command, it's a bug in vanilla that can easily be recreated with giving yourself infinite actions with the console. It also drives me absolutely crazy when trying to repro certain bugs that require me to move a lot as I spent 80% of my time restarting the game
Re: [1.4] Command move crash bug
The best workaround to avoid the crash here is to issue the first blue move command, then tab to a different soldier and wait for the move to complete, and only then tab back to the soldier/unit with the extra move.