Unable to attach a behavior to an actor or otherwise modify the actor

I open the actor, switch the the Behaviors tab, click Add Behavior, select the behavior to add, and I get an unexpected problem dialog. Here are the logs.

My subscription is coming up for renewal in a couple of days, by the way.

Thanks for the report. It was bugging out when there was an unexpected entry (not name=value) in the dropdown data for an attribute. Fixed in build 8390.