[REG 5.11 -> 5.12] Enter/leave event doesn't work properly

Enter/leave event doesn't work properly since Qt 5.12 on Windows 10:

Case 1:

• press left mouse button (e.g. on text edit when cursor shape differs from arrow),
• move mouse outside windows,
• move mouse to initial position,

Current result: we've got a leave event only and mouse cursor shape is arrow, not text cursor.
Expected result: no leave and enter event when moving mouse with button pressed.

Case 2:

• right click to open popup menu (e.g. on text edit when cursor shape differs from arrow),

Current result: we've got a leave event (sometimes not immediately) and cursor shape is changed into arrow. After closing popup we don't have an enter event, so cursor shape is arrow, not a text cursor. Since now we doesn't have any enter/leave events for window.
Expected result: enter event must come when popup is closed. Also enter/leave events must work for window after closing a popup.