I tried to reproduce, but behaviour appears to be functional. In the save I provide, if either Lucas or Ren move north without facing into the barn they'll get shot at as they have practically no TUs left and the sectoid inside has full TUs. However, if Lucas sidesteps to the entrance of the barn they won't get shot at even tho their reaction score should be almost non-existant, same for Ren if they move diagonally towards the same entrance.
The 3rd unit, Hanne, is at full TUs, if they move south not looking into the barn they'll get a reaction shot, if they move diagonally towards the entrance they'll spot the sectoid and not get shot at. At this point if Hanne moves to hide behind the barn wall next to them, turn to prepare for a side-step and move out doing so, they'll get reaction fire because their mutual surprise has already been triggered from the previous spot.
All of the actions detailed were carried out both on OXCE 7.15 and 8.0, behaviour is the same on both.
Also tried loading the vanilla save provided, but results are exactly the same, side stepping at the barn entrance after wasting TUs (2 auto fires into cabbages) prevent reacction fire, walking without side-stepping will draw fire.
