I don't get how Sonarr parses release group names

Hi. This topic

My Car Is My Lover-YTDL

becomes

Strangelove.2008.S01E01.My.Car.is.My.Lover.1080p.HDTV.h264-SONARR.mkv

and

Married.to.the.Eiffel.Tower.PDTV.XviD.MP3-MVGroup.avi

becomes

Strangelove.2008.S01E02.Married.to.The.Eiffel.Tower.SDTV.XviD-SONARR.avi

I don’t get what I’m missing when

BBC.Arena.2018.Stanley.and.His.Daughters.720p.HDTV.x264.AAC-MVGroup.mp4

becomes

Arena.1975.S2018E01.Stanley.and.His.Daughters.720p.HDTV.x264-MVGROUP.mkv

I just assumed anything at the end of a filename after a dash would become the release group and was wrong. I wondered if it was a scene naming thing but the Eiffel Tower and the Stanley ones producing different results has me stumped.

These files are all manually imported. I get the impression there’s no appetite to have this field be editable inside Sonarr, which is understandable. This happens to me a lot and as much as I dont mind digging through my folders occasionally to catch these I’d much prefer to be able to predict the outcome when I’m getting files ready to be manually imported.

What am I missing?