I reported now general texture display issue for the 8.4.2 as new issue / the first issue was for the 8.4.1 - vuforia view crash for model with texture. Reported to internal R&D community.. I will wait 2-3 days and if there is no answer will log direct R&D ticket.
I also have the same problem with the version 8.4.2 , since I upgraded the textures are no longer visible. with the previous version they worked very well. :-(
THE PROBLEM IS THAT CUSTOMERS WILL NOW DISPLAY EXPERIENCES WITHOUT TEXTURES. THERE IS A WAY FOR A DOWNGRADE.
The earliest that we'll see a fix is when 8.4.3 comes out which according to the PTC Product Calendar is due on 9 May.
Well 8.4.3 was released and I'm very pleased to see that the problem has now been fixed.
8.4.0 - My model with textures worked
8.4.1 - My model with textures crashed View
8.4.2 - Textures support for HoloLens removed completely
8.4.3 - Textures back and my model with textures works
Thanks @RolandRaytchev for your help with this.