I got a couple of CTD's in battles and was worried, but I'm almost certain it was because I tried to get the skymod to work with EB and in the middle of a battle (not when any new units were first shown or anything, but sorta like when the sky or weather would change) I'd get a CTD. I haven't had it happen since I removed it though. Otherwise I haven't had any in battles and I've not had a single one occur during turns on the campaign map. And I've been playing through many years testing things out.