Teo3 This kind of path is variable reference path that should be resolved on RN preset import. It is expected that it fails to save such path as it does not exist without RN internal parser.
To use those models in own preset first import preset with RN (not 3dm directly) then use imported blocks in own preset and save it. Let me know if you'll need further guidance.
P.S. variable reference paths were provided having content creators in mind.
