I've had this happen a couple of times on different maps (base defense & the small village map where there's a red phone booth just after crossing a bridge - don't have game loaded up at the moment to say exactly which it is) but it seems when you've got 4+ area effect grenades like smoke/gas going at the same time that a crash to geoscape will happen at some point during the aliens turn. I didn't get a log yet but will try to set it up to get one but just giving a heads up to maybe test it. I had the slow frame refresh rate problem when a smoke/gas grenade was going until I applied a fix mentioned in another topic & things had been working fine since. I'm using 2.5 dev Nov5th version right now.
