layer: flower.leaf bottom right of the map -> third flower from the right -> the leaf on the top left has a quad just to the bottom-left of it. That quad is invisible, rightclicking it crashes the editor. That is because it references an out of bound color envelope (index 3722).
Since it is invisible anyways i removed it. However, since quad data is compressed, i couldnt simply use a hex editor. Instead i used my library and wrote a script for it: https://gitlab.com/Patiga/twmap/-/blob/master/src/bin/fix_map.rs
I have tested the fixed map in the editor and also on a server + a client joining, playing through the map. However i encourage any more testing on my library and the fixed map.