As I said, I don't really know what I'm doing..
The editor crashed while I was playing with it, so I remade the model here: (still the same error)
https://editor.aifiddle.io/models/cloud/9f33d272-5aab-40eb-8...
Maybe the last reshape is not actually legal since it reduces the number of values?
edit: Yes, I think that's it. Using Dense instead works.