I don't think it's a good idea to release a "stable" version of Ubuntu with such a bug... which has an importance more than medium... the system is unusable out-of-the-box (once desktop effects enabled).
Removing --loose-bindings avoids in majority the problem, but this morning, even without --loose-bindings I had the problem once.
Maybe downgrading to 173?
I don't think it's a good idea to release a "stable" version of Ubuntu with such a bug... which has an importance more than medium... the system is unusable out-of-the-box (once desktop effects enabled).
Removing --loose-bindings avoids in majority the problem, but this morning, even without --loose-bindings I had the problem once.