teammate is faster than me at 400m and 8k, but slower at 800-1500. hows that work?

One of you guys is under-performing in some event. Maybe he's under-performing at 800-1500, or you are under-performing at either 400 or 8k.

There is always the possibility that he is bad at cross country. I'll use myself as an example. There are 800 guys with better leg speed than I have who beat me at cross country who I would absolutely crush in anything 1500 and up on a track. This is mostly because I just don't run up hills very effectively.

Good aerobic capacity and leg speed, but bad anaerobic capacity? Seems possible.

Yup This happens, I have multiple teamates that beat me at 800m-5000m distances. But none of them come close to beating me at 60m-200m and the 400m and half marathon I am stronger. The 10km we are very similar.

My theory on it is that people like me did sprints or short stuff and focused to much on base work (easy runs, long runs or long tempo stuff). The trend on training these days is build up the miles and to not load up on intervals like in the 90s if you want long term results. Well so far it's not working for me unless I want to consider myself a half or marathon runner then yeah I got better.