See attached application that demonstrates the problem, juts compite MenuFrame and run it, then:
Under "Versioning" menu there are three conflicting mnemonics 'S' for "Status", "Push other" and "Subversion". Although "Status" is first it does not get selected by Alt+V and "S". Then next presses of "S" key cycle only between "Status' and "Subversion" items, "Push other" is never selected.

Note that error is visible only on GTK L&F and Metal L&F, on Win L&F on Win machine it looked all OK.

Originally this issue was reported against Netbeans IDE, where it has more consequences that I'm unable to reproduce in test example. For details please see
http://www.netbeans.org/issues/show_bug.cgi?id=129146