Three off them, all very annoying:

1) When building a bunch of quanta with engineers, I was unable to place in certain areas, but if I placed somewhere else and then reclicked the original area, it sometimes worked. Something similar was happening when building the mines (on the actual circles and triangles) -- sometimes would refuse to place the mines.

2) On at least one occasion, the engineers too orders, but refused to build. The just stood there. This was awful. I had three engineers grouped together.

3) On two occasions, I became unable to select an army. When I clicked on the units, I would get a sound like I had clicked somewhere inapropriate (a low bounce-type sound). I tried to disband and reform, and still failed. Also, I was unable to box the units, and had to select them individually to regroup. Ultimately, it seemed like I was able to get the units to move together, but only one or two would highlight. Very very very annoying and evidently buggy.