@Zackan1, you have to install PREPAR3D4.2.
4.3 and 4.4 are not compatible with Pimax yet till they update the mesh in PITOOL
I do think that the pimax team is busy with more prioritary tasks now than dealing with this issue.
I´m also having this issues with P3D V4.4 and Pimax 5k. With the box checked, my screen is split up in 4 sections. Please Pimax! It would be nice to fix that bug. Otherwise I will have to stop using Pimax. The only reason I bought it was using it with P3D V4.4 and upwards. Thanx a lot in forward. Would appreciate your help
Iceman2 from avsim posted a solution that I can confirm works.
"Sadly it’s back in PiTools but working normally for me when not checking the Hidden Area Mask box.
If that still doesn’t work for you. Uninstall PiTools and manually delete all Pimax folders. Then reinstall Pitools 1-0-1-112 Make sure the hidden area mask box is unchecked and make adjustments to all other settings as desired. Then start Steam VR from within PiTools then start P3D."