I know it's no more than partially helpful to you, but I've deviated from courses quite a few times since 18.25 was intsalled and the device has never crashed (famous last words...). The only thing I find is that the options to paue navigation or reroute simply don't work - it re-routes whatever I do.
Anyway, it sounds as though there's a difference in the way our units behave. I have no IQ apps installed, except for mybiketraffic (which isn't navigation-related), FWIW.
