I have the same problem. The Alt key works most of the time, but not always. This is very irritating, especially when you cant set a shortcut to Project panel, etc.
I have the very same problems with PPro 1.x and do not have the same problem with any other Adobe apps, so this is a “PPro-error-only”.
The F10 key triggers the same thing as the Alt key but when the Alt key stops working the F10 dont respond anymore. (For example, F10+W+R brings the Project panel to focus.)
/Roger