Editor loads wrong textures for custom shaders

Download the archive from the folder QT3DS-4072 on our FTP server. Run the EarlyCluster/DriveSpeedControl/DRIVE_3212_Group_ADAS_VIEW.uip in 2.6 editor. Run project in viewer.
Expected result:
Right rectangle in the editor will look like in the QT3DS viewer.

Actual result:
QT3DS editor shows a black rectangle for the custom shader.