If you in a fragment shader call texture() multiple times with different textures you get the following problems

• text in Quick and Quick Controls item gets corrupted
• one of the textures are rendered on the scene (even though the current shader and geometry should not render anything)

The problem disappears if you

• resize window
• change renderPolicy from OnDemand to Always

Other notes:

• problem not seen with Qt 5.12.7 or Qt 6.3.1
• attached image and project example