Perl sleep on windows in a VM or 100% CPU usage or C debugger breakpoints, or bad driver that likes lock all the CPUs and then spin sleep for too long to freeze the PC can cause an overflow in Perl's sleep, and then only a random Windows message (mouse move, repaint, idk what else, but there
WILL be one, thx MS) will breakout of the sleep hang, see
https://rt.perl.org/rt3/Ticket/Display.html?id=33096 causing the sleep to take more seconds than it should have.
win32/win32.c#l2163 in perl.git for the offending code.