I've made particle system based on single feather alpha and to color it I used color map based on main object. Since it has UDIMs I used them as well, just scaled color map to 512p to save space. All worked just fine in viewport, but when I decided to make test render - it was all wrong. To make it more interesting the other particle systems which only used paths, had correct colors in correct places. I tried everything, and finally found solution - I isolated texture tile mapped to main body, where most of the object particles were and it suddenly worked.
Could someone explain to me what's happening here? Why this particular fix worked? Are UDIMs not compatible with object particles?