Hmmm, again, which layout? I've tested Kunos and most of the ACC mod GT3's at 100% S&A on all layouts, and haven't had that problem. If it's repeatable incident, see if it is the same car causing problems. If so weed it out, and see if that helps.
I can't ever guarantee the track ai will work perfectly 100% of the time with all the mods out there. It's a hand in hand relationship between the track and car's ai, to make it work. Some cars have better ai built in than others. PM me and I'll see if we can figure it out.
edit: here's a screenshot of the GT3's I tested. Ran several short races without problems, on long and wtcc layouts.
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