The STR's in general have been awful with traffic this season.
I noticed on mistake at Monaco, and that was one of the STR's not allowing Jenson through after he came out the pits. Jenson rejoined the track all over the STR but it simply did not give. There were no other cars nearby, and it was up through rivage. The STR could have backed out the throttle easily enough but refused. I was very surprised a penalty was not given because it was clear, obvious blocking.
As for the incident, that was caused by too many cars trying to fit into a space too small caused by some eager young guys hoping for a result. Was more like a GP2 incident than F1.