You’re welcome. At least this can be used as a workaround for you if you want to reply to someone’s message; for new threads this will not work of course, but then, there’s still the “oe”-Workaround 
Anyways, I’ve started a 7.1.0-rc Deployment here to see if this is still an issue and the goods news: It’s not. So this problem has already been identified and fixed as it seems and it’s not client-side, but serverside.
I’m connected with my 5.1.1 desktop client to a 7.0.1 server and to a 7.1.0-rc server; the latter does not break when you type CTRL-ALT-p in the message formating toolbox.
Best,
Alex