What happened to the solo_female tag?

It currently redirects to solo male which cant be right.

There are no aliases or implications between the two.

The solo_female tag is currently empty, so I think that the system thinks it does not exist. The suggestion between the two is coming up in the tag preview popup, and I think is being automatically created by the preview suggestion system because the first tag is empty, so the system is guessing to the closest similar name as to what you might want.

just use solo and female separately

There used to be that tag, did it actively get removed? Really fucked with my tag search muscle memory

It was not so much removed as someone emptied it. Tags are not so much created or destroyed as they live and breathe by whether or not they have any members.

As to who or why, I don't know. And with the log of tag changes being multiple months behind, there's no easy way to figure it out.