Never done proper EVP work myself but I've noticed something similar with time slip reports - a lot of the more vivid accounts seem to cluster around certain lunar phases when you dig into the dates. I started tracking it a couple of years back after reading through old case files and the pattern kept jumping out at me.
Whether thats the moon actually doing something or just us being more attuned and receptive during those periods, I genuinely don't know. Hard to separate the two.
Would be curious whether anyone doing EVP sessions keeps a proper log with dates because that raw data would be fascinating to look at over a longer stretch of time. Even just a year's worth of sessions with quality ratings against the lunar calendar could tell us something real. Anyone actually doing that or is it mostly just impressions people have noticed?