Hello,
Have you tried Internet Explorer? Do you mean the typing issue only occurs on a specific website while working correctly on all other websites?
You may try the solutions suggested in this thread; Powershell 5.1 not accepting keyboard input when using Remote Desktop HTML5 Web Client - Microsoft Q&A The solution involved enabling the input method editor at the client side.
Other reference: Keyboard settings in the remote session
Regards,
Karlie