Since I upgraded to Build 7.0.14924 (localized german edition, running on Lion 10.7.2), I have the following problem:
Every time the Parallels VM window looses its focus and is clicked again, all keyboard input appears in capital letters only. The caps lock LED is dark at this point and only letters are affected. If I type a number, I get the number and not the shifted character on that key !
When I hit the shift key twice, the behavior returns to normal again.
This problem appeared sporadic since Parallels 5 or earlier.
Now it happens permanently, exactly since this particular build number.
Hope this helps to track this issue down.
See bug report #10749915 for system details.