Depending on what powered the shield, plasma would've usually disrupted them, since it was two consecutive blasts it also would have been intensely hot, maybe even enough to melt through the armor. On top of this, once it melted through, the armor would be venting atmosphere, and with no breathable air for the aerobic Equestrians, they'd certainly meet a grizzly demise to suffocation.

They should at least be somewhat damaged by the blast. These ain't rocks, son.