Yeah it's not just mash-up packs, it's ALL of the texture packs. I saw a thing saying there was a fix but it's still just as borked as it was before. The textures aren't loading and I'm still getting the weird black & pink checkered stuff. Oh and it crashes my game when I actually try to use them while playing.
I actually got the Pattern Texture Pack through the new version and it's not working. The only pack I have that seems to work at all is the new Cute texture pack, but only on the menu screen. I still can't actually play the game whenever I try to use a texture pack. My game continues to crash to the Switch homescreen every time I try.
There also seems to be no option to export worlds from the Switch into a file on the computer (much less mobile where I am typing from) so those instructions are unhelpful. Realms also still seem to be unavailable. (Not that my subscription thing is currently active)