Please check the classes & characteristics assigned to your source material. I'm pretty sure those contain reference characteristics that reference a field of the material itself. These chars cannot be set, as they mirror one of the material fields itself.
See here for details: Creating Reference Characteristics - Characteristics (CA-CL-CHR) - SAP Library
This is of course a bug, and if the SNOTE
2105519 - Reference material with reference characteristics not transferred completely
is not fixing it, then you should open an OSS for this.
Kind regards
Jürgen