I made a 1v1 map and I didn't touch anything with the race matchups.
when people play my map they are gettting the same race too often.
they both go RVR and after 5 games they will get pvp tvt zvz vzv tvt something like that
the same races
this doesn't happen all the time. but it happens enough for me to wonder....
Can someone help me make a trigger or whatever to random their races properly?
None.
Tho I have no clue as to how SC2's stuff work
I'm pretty sure it's just some freak coincidence.
Even if it isn't, it probably has nothing to do with what you have triggered, meaning that the randomizer that Blizzard uses isn't that random.
There's nothing you can do really...
on the other hand, I'm sure someone will tell you how to randomize stuff with triggers
None.

I do stuff and thingies... Try widening and reducing the number of small nooks and crannies to correct the problem.
You can't change the race ingame (GUI and announcer) as far as I know, so it is impossible to do it properly.
You can only spawn different buildings and clear the creep.
So best solution would be to hope that sc2's random is really random.