OK, I have tried some things and here are the results:
1) Turning the console off (completely) and then on again, solves the problem, until you repeat some actions.
2) Went through the Community Decals in an effort to load the console's memory and see if that is the problem. Here is what I've found:
a) The crashes start happening again, even if you don't go in the Editor.
b) Crashes don't start happening if you don't change anything, but only view other wraps. I kept my Custom Wrap which was making the game crash before but it hadn't crashed after the console reboot.
c) Crashes start happening if you make even the slightest of changes (for example, loading another community wrap on your car but don't go in the Editor).
d) If you go in the Editor or load a wrap on your car, go through the Performance Menu before exiting to the Free Roam (this seems to dump the files that cause the crashes from the RAM). I have not tested this with many other variants, though.
e) DO NOT EXIT the garage THROUGH THE MAP! This had always been a problem in my tests. Instead, exit using the Circle button, choosing a time of day and then choose a destination.
3) Time of day, skipping the race intro or not, time played in the game, other cars or racers and weather effects ARE NOT relevant.
4) Rebooting the console a second time solved the issue again, until I repeated a trigger-action.
5) After a crash happens, the game will be crashing every time you start playing it, no matter if after restarting it you do something that triggers a crash or not. You are safe only if you reboot your console and start the game again without triggering a crash.
6) I could not perform any more detailed tests since I only have the Free Trial version.
I hope this helps a bit.