Certain ICO files display with significant artifacts after loading

In debugging the favorite icon download feature for KeePassXC I came upon several websites that have their favicon files showing as corrupt in our application. I thought it was something we were doing when handling network data, but it also occurs when loading the same ico from disk. I then thought it was a problem with QImage::scale or the conversion from QImage to QPixmap for display in the GUI, however I have ruled out both of those cases as well. This leaves me to believe the error is occurring directly in the ICO Image Format plugin. This does not occur with all ICO's but I have two samples from Delta and LinkedIn that show significant artifacts.

Our icon handling code is found here if you want to review it: https://github.com/keepassxreboot/keepassxc/blob/04983ce4cd3ca3e835e05b627907859ac97db5d3/src/gui/EditWidgetIcons.cpp#L378-L406