I could swear there was a rule about the max distance between "tap" (to bias the substrate) and nmos, but I can't find any looking in the "periphery rules".

@Luis Henrique Rodovalho Thanks !

15um always seemed weird to me. Usually I have seen taps range from 60um to 30um at the smallest. 15 seems too small to me. I've never seen a DRM from skywater saying that 15 is the max.