Yes I have! A member from unreal has seen my question and forwarded this problem to their team. I hope this gets fixed soon.
I have also recreated the same timing difference in my DAW, by manually delaying and summing the metronome samples, then comparing the summed audio to my recording.
The timing difference creates clear notches in the spectrum that can be used to identify how many extra samples the Wave Player node has created, which turns out to be 1 extra sample per loop.
So in my case, when I tried to loop a 96000 sample file, the Wave Player looped every 96001 samples.