Why does the gene SHANK3 not show transcript NM_033517.1?

SHANK3 is quite a problematic gene. Alamut^TM Visual Plus mapped the available transcripts to genome builds and NM_033517.1 could not be mapped to either genome build, due to mismatches between the transcript and builds.

We do, however, have a RefSeqGene NG_008607.2, which is based on the transcript NM_033517.1