Well, more info about the case:
Step one. Client going to connect to the host (let's name it "host A") in "Full Access mode" over internet.
After connection let's test keyboard and see if it working well. Yes, it's working.
Inside host screen open client to remote computer and connect to another host within local network (let's name it "host B") . Testing keyboard, and No, it's not working.
Step two. Create new connection in viewer to "host B" using "host A" as intermediate connection - Yes keyboard is working correctly.
Step two working as workaround for the problem.
It's may help you to reproduce the problem in your lab environment.