I have the exact same issue. I'm on Horizon 7.5 with the agent 7.5 and the clients range from 4.6 to 4.8. Thinprint is not taking the client side settings to disable printer redirection. I even looked at the article to unload thinprint RDP DLL and that didn't work. I do not want to disable thinprint as there are use cases when users work remotely that it's is useful.
Anyone else have this exact use case?
Sounds like you may need UEM Smart Policies to do this task. You can enable printing on-prem but disable for remote users coming through your APs.