I'm not gonna lie, I feel that this is happening quite a bit. There are a few players that when I'm against them in WZ's, my packets will spike enormously throughout a match -- as you said -- at critical times.
OMG!! I just returned from the game after a LONG break.
First thing I noticed, against 'specific' players I suddenly spike huge lag bursts, can't function properly, cannot hit buttons, etc. This happens repeatedly with these same players, every single time I face them. They have unrealistically high performance at the end as well. Extremely suspicious.
I am not quick to claim hacks, but my first impression was - this is a hack.