QAccessibility test fails on Windows 8

in textEditTest(), pass 1 (Helvetica 12.5 font):

FAIL! : tst_QAccessibility::textEditTest() Compared values are not the same
Actual (iface->textInterface()->characterRect(offset)): QRect(677,510 15x24
) (bottomright 691,533)
Expected (characterRect(edit, offset)): QRect(677,510 14x24) (bottomright 690
,533)
.\tst_qaccessibility.cpp(1585) : failure location

This failure really happens only on WIndows 8 (as opposed to others which are triggered by the Aero style). Not sure what the cause is here?