Sure. Some genes were retired because there was not enough support. Earlier Ensembl versions used older genome assembly. Which means: some genes "jumped" from o

Sure. Some genes were retired because there was not enough support. Earlier Ensembl versions used older genome assembly. Which means: some genes "jumped" from one chromosome to another, or got properly stitched residing before partially on floating contigs. Just to be clear: I am not saying that anything done in 2022 using hg19 is 100% wrong. Just that it is a bit like using a stretched shoelace 50cm (+/- 5cm) to measure your corridor when you have a decent tape measure in your pocket. There are microarrays used in Big Science projects with ~1/3 of probes not matching human transcripts from latest ENSEMBL. Since most of them map to the current genome who knows what is the meaning of the signal from such probes. Unannotated exons? Retained introns? But some probes do not even map to the genome => some silly splicing error(?) packed in a plasmid in the 90ies?