I am always designated to defend alone against the Voth at the Generator 2 (the northern one which is considered the hardest or at least not as easy as Gen 1) and it is really not that difficult, if you have any advanced knowledge about the game mechanics. there are TONS of different approaches, which makes even the voth…
it does show the stat buff though - it´s a 0.5 buff instead of the tooltips 50 buff it either should not be visible at all as it doesnt buff overall stats OR the real buff. in the current state you can´t say if the battery isn´t working as intended at all, since it shows a 0,5 buff which is useless