[Reg 6.6->6.7] Funny theme icon

The new icon platform engine returns a weird icon for "edit-clear": See the locator input field in Qt Creator:

All (the vertical bars and the X) are in the icon.
When I look at what Mail and Finder use, that looks completely different:

Another strangeness is that we request a pixmap with
icon.pixmap(size, pixelRatio, ...)
with pixelRatio 2, but we get a pixmap with devicePixelRatio 4 back - is that supposed to happen?
"size" is 32x16 in this case, the resulting pixmap has size 128x64 dpr 4