I've asked fellow artists with previous experience with 3D coat about this issue and also I tried looking for a solution in the 3D coat forums to no avail, we don't have any idea of what's going on.
I'm currently working with this model and when I edit the projection in photoshop... 3D coat will project it on random areas. We've checked the UVs, tried painting in other software such as Substance Painter and we cannot replicate the issue I'm experiencing with 3D coat. We've tried older versions and they all have the same problem as well.
I've tried painting the model and it does the same, undesired areas of the model gets painted. I'm attaching 2 gifs from 2 different 3D coat versions. The safest bet was changing the padding settings but this didn't fix it.
Thank you so much!