I've been trying different parameters for creating a model of a large area with a group of buildings (3,250 20MP photos). I made several models fine, but they all were 3D instead of 2.5D Height Field. I decided to try the Height Field as I think that's more appropriate for planar surface. The model generated fine, I limited to 15 million faces (same as before). Arbitrary Texture, Mosaic blending, 4096 x 16 (before I used 8192 x 10 so memory requirements would actually be a little lower for 4096 x 16). I have 120GB of RAM and Tesla M60 GPU.
I ran a batch process overnight and woke up to find the Metashape in the "Not Responding" state and was stuck blending textures. This was all on version 1.6.2. So I upgraded to 1.6.3 and restarted the texture process. It took about an hour to finish the parametizing step. It got 1% into blending and now not responding again. However, in Windows performance monitor I can see it is using CPU (around 13.5%) which typically indicates it is doing something, where as before I think after overnight the CPU had come down to 0%. However the memory usage is not changing at all, so that indicates to me it is indeed locked up, maybe in some sort of a loop?
Still I have very very rarely ever seen Photoscan/Metashape go into the not responding state.