FWIW, this is the same issue I have. It started after 1.6.27, and has persisted all teh way up through 1.7.11 as of my own testing. You can revert to 1.6.27 and that will get the terminals working again. They occasionally still hang and you have to fiddle to get things working again, but for the most part 1.6.27 works and terminal usage by the agent works, whereas anything after that, and terminals DO NOT seem to function.
As far as I can tell, a terminal instance is not even being created, so you can’t even open it and check on it. The agent seems to hang here before it even creates a terminal instanc.
See my issue for more details: