Only work around for the moment: Install Stable 2.5 again. None of those work arounds mentioned on 18 (!) pages before did work for me. Independently of the game mode used the game crashes on the second flight. I have observed it so far on those modes and after hitting in debriefing fly again or pressing LShift+R in the mission:
Instant action
Fast mission
Mission (SP/MP)
Campaigns (Rising Squall checkpoint feature is currently useless)
Even a full re-install, with mods or w/o mods, plus all the tipps mentioned before. Never had any issues with DCS World betas before 2.7. ED, please stop any work on new features and bring this piece of scrap to a level of maturity that deserves being called "beta".