You should update as soon as possible.
The gist of this error is that we tried to ask the Perspective session running "inside" the designer for your session prop configuration + a particular view's configuration. We "ask" for that, then wait 30 seconds, and if we don't get a response, give up.
If that happens and you save, you could potentially overwrite valid configuration with nothing, effectively deleting resources.
In later versions, we've fixed various bugs on the frontend that cause instabilities, and upgraded JxBrowser. We're also in the middle of updating the browser library again to the absolute latest, which should hopefully help with this issue more.