Window reveal surfaces disappear in Host file after reindexing

[Stefan Videnov]

Hello, 
I've reindexed the Surfaces of the windows in both the Source and the Target file in order to fix some attributes mishups.
Now (maybe related to that above) all the window reveals appear black in the Target, but good in the Source. 
I have not reindexed the brick texture that's supposed to show on the reveal

Target:

Host file:

Additionally all Niche window objects also decided to turn black. Previously they were set to display the host  wall Surface. I managed to fix them by giving them the specific Surface

Any Ideas on how to fix? 
Thank you! 

Operating system used: Windows 11

[Stefan Videnov · Accepted solution]

I came to the conclusion that It's a bug where Archicad 27 Windows do not act as they should in Archicad 29.
Basically windows get very very confused about their textures. Sometimes the textures go missing, sometimes they don't get transferred properly through hotlinks etc etc.