In beta version 7.63.416 I tested it and I don't notice any accentuation failure even though repeating the sequence quickly.
As this issue appears for you in the latest beta, the most likely reason is the change to allowing on KEYDOWN in all windows.
Can you try this in beta 7.63.416:
1. Create a custom @window with an editbox: /window -e @test
2. Type your accented key in the @test window. Do you see the issue?
3. Now type your accented key in the status window. Do you see the issue?