[GAMEPLAY] Unable to flash with mouse button while holding shift for attack move

I'm certainly positive this is a new bug that came with the 9.9 update as I've never encountered this issue prior to the update. I use MB3 (mouse scroll wheel button) to flash. While holding shift for attack move, you cannot flash while pressing down on shift, it also does not matter what mouse button you map flash to; it will not go through for any other mouse buttons as well. You can, however, flash just fine while holding shift if mapped to a keyboard button.