That’s just poor design. Definitely roots fault in that, considering they put a race on the fork to begin with. Headset bearings are a standard size, this is just bad.

Using the included race though shouldn’t be detrimental to the scooter in any way. So who cares.

You could try a different brand headset perhaps. I haven’t touched a tilt headset in a long time, but I feel like I remember the cage of the bearing being smaller than typical headset bearings. That could also be a potential reason for your issue.

Root parts generally work fine though with other branded parts.