Hi, this is not the intentional behaviour at all, please report a bug: https://github.com/Dangry98/PolyQuilt-for-Blender-4.0/issues/new
I am unable to replicate it on my end, so please make the bug report so I can investigate furter.
Been using it for a short while and it's pretty great. Thank You for this addon
When holding shift to create polys, you can no longer see the preview of the polys, you used to be able to in previous versions. Works well otherwise.