It is not handeled for different spells/effect the same:
Mindweaver / Parasite Swarm:
A freeze, oink or paralyze effect stays on the unit after it was taken over und runs out normally.
A single freeze, oink or paralyze effect gets canceld after the unit is ztaken over with a "Mind Control" spell. When there are two effects of those kind are at the same time on the unit, the effects stay on the unit after is was taken over (similar to Mindweaver / Parasite Swarm). So i guess there is a bug with "Mind Control" with single freeze, oink or paralyze effects.