Epic Success on Haywire Protocol gives Best Result?

[Mooncabbage]

So, I had my specialist use haywire protocol to stun a Advent MEC, the first i'd seen in this campaign/patch. Only a 54% chance to stun, less to control, so I went with stun. Specialist rolled very high, and the MEC was stunned.... and then it wasn't. Now I have control of it? Is this intended behavior? Specialist definitely rolled high enough to get the Control option, but I had the Stun option selected... as I understand, that should disallow control?

[Mooncabbage]

Update: Although the MEC was under player control, and marked as as hostile to ADVENT forces, it had no actions, and was essentially "stuck" as though stunned.