When I was doing testing for the buying Chinook CTD bug I also ran into this CTD in any of the test games I went past June 20th. The date and time for the CTD was never fixed but only ever seemed to occur after June 20th, June 30th was the longest I ever got before it CTD. Even the my test save that I reloaded many times didn't crash on a specific date, but was usually around the 23rd.
I only tested it on x3 and x4 which both had similar results. In all the games I did nothing but simply build hangars and a second base, but when testing this specifically I did nothing at all so maybe it had something to do with my bad performance(?) or perhaps is related to a spawn or event as those don't occur at fixed times afaik.