Without knowing more about the bikes you’re comparing it’s difficult to offer much help beyond idle speculation. Given that caveat I’ll take a stab at this. My suspicion is that your “real” track bike has greater trail and wheel flop than what you’re used to riding. The fork is likely to have 35mm or less rake and with very narrow tires will work together to stabilize the bike at high speed but do the opposite at lower speeds which you might perceive as the bike wanting to oversteer.

Take the bike for a ride and get it up to a fast pace and maintain it for a bit. If you notice less twitchiness at speed then we’ve found our issue.

I know a couple of ways to address this, I’m sure some folks know of others. The simplest and less impactful change is to swap out your front wheel. A wider tire will impact mechanical trail but some folks report the rim itself can play a role in this. The next step is swapping out your fork. Your steamrollers fork should slightly mellow low speed handling.

What to do if this is a rake and wheel-flop issue and you don’t want to mess with the fork? Well, you might look at handlebar width. This isn’t an area where I have a lot of experience so hopefully someone else will chime in. I’ve read that narrower bars can make a bike less twitchy. However, wide mountain bars always make me feel like my weight is better distributed and hence the bike feels more controllable.

I don’t think a shorter stem will make a bike feel less twitchy. If anything taking more weight off the front tire will have the opposite effect.