When rendering, Premiere automatically adds a “-” to the file name

You are having a rather rare issue, that is apparently quite localized when it happens … and they should rebuild the entire app? Huh.

Undestand, I totally agree that that behavior you’re getting is wrong, it’s annoying, and us peers would love to get it behind you. And it is frustrating we haven’t been able to help.  So you have total sympathy while we live in reality. Ain’t none of these apps perfect, and there are frustratingly issues that pop up on a few machines that are dangnably idiotic and angering. Yup.

Got friends on other apps having also odd but clearly rare issues.

I’ve seen this before - usually there’s a special character in the sequence name, sometimes it’s not even visible in the app, and Media Encoder is trying to avoid it.

Try copying/pasting your sequence name to a format stripper like this one below, then paste it back and see if it fixes things.

https://convertcase.net/remove-text-formatting/ 

I’ve never seen this behavior, ever. Not in the past, and not now. So I’m thinking it’s something local that’s the issue. Have you dumped the cache files on startup?