This appears to have been fixed with the most recent update. Now the troops maintain formation and don´t get stuck behind hills anymore. They somewhat spread out when going through thick forested areas but they now always recover and catch back up with the leading unit. No more eternal suppression and no more getting-stuck-while-standing-inside-each-other. 👍
Do NOT delete the JF-17! I did more testing today, deleting most units in the editor and then launching the mission. By deleting units until it didn´t crash on load, I narrowed it down to the units on the airfield the player starts at. But then, when I thought I found the units that caused the crash, the mission stopped crashing even with the units present!!!
I have no idea why this happens, but the mission works now, even when no changes are made... It crashed yesterday even after restarting my PC, it crashed today unless I delete the units parked on the airfield, but now it just works even if I don't delete any units!
So you don´t have to change anything, this might just be some very weird DCS bug...
Thanks for responding to my bug report in any case.