As mentioned in one of the previously linked threads, where this error is coming from has already been tracked down: It's in OvrAvatarMaterialManager.cs, lines 185-191 of ProcessTexturesWithMips(). The only way to suppress the bloat is to comment out the entire TextureCopyManager.CopyTexture() call, which will make every part of the avatar except the hands invisible. I can't speak for other people's experiences, but if I'm taking the content of the message literally, it seems that it's mad about copying a mip for a texture to ASTC since I'm developing for the Go.
Again, this is a linear issue: every time a new Avatar is added, you get another firehose of ~100 error messages. When spawning Avatars is happening in the context of the initialization of a multiplayer session (and why wouldn't it be, in this case?), you get ~100x however many Avatars you're spawning in. So, in my workflow, it makes picking up on certain other things that I'm trying to debug in logcat at the same time impossible. Most of the time, the buffer on my CLI shell is totally full and I can't see anything that happened before I got a blast of CopyTexture warnings.
In general the Avatar SDK needs a lot of love on the mobile side, as it's very expensive and inefficient with the marshaling from the CAPI and really seems to have just been a quick proof-of-concept on making the Oculus Home/full PC SDK "work" on mobile. But at the very least, can you look into this issue and patch it in an upcoming release? It's very, very annoying to have to deal with.