I was looking through some other game jams and I thought I saw some unfinished WIPs uploaded so I uploaded my own barely started game because use I thought that's what everybody was doing. Then I had another look at the other jam entries and they all seemed to be finished and I'm the only one who's done it on this jam. Have I committed a faux pas? This is the first jam I've entered and I'm not sure how it works

I considered doing the same when I have something roughly playable, as long as you keep updating the version it's actually a good way to get people interested in the jam process.

Don't worry, I did the same. As soon as I had something playable. (It's not yet what you'd call a 'game')