Got any pics to show the damage?

Definitely not cool on the part of the maker. Just my guess - It sounds like they did not protect the handle and pushed it in and out while the unfinished work in progress kydex was tight and had sharp unfinished edges.

Others probably have more experience and can comment more but I suspect that while res-c is hard, I am not surprised that a sharp kydex edge would cut it, particularly if forced.

If you're unhappy with the sheath why not have Rainwalker make you one. He is a regular on this board and his work is top notch.

Neal