Eevee Gender Ratio Changed! (Temporarily)
I think you need a muuuuuuch bigger sample size for it to even out into actual results? I don't think it's exactly a bug or anything, just a bit of nice luck!Bulbapedia still says that it's a 1:7 ratio for Eevee, and in the case of Gen 8, that'd rely on the gender threshold for Eevee (00011111), so if you'd like you can look at the hex values yourself somehow — but I think that if there was any change it'd certainly be noted on the page?
Especially because Bulbapedia also notes that yes, there is difference in gender determination between generations, but the 1:7~7:1 system is still kept. Also note that due to a glitch in the Gen 8 games' code, symbol encounters have a 1:1 gender ratio, which could have also interfered with your mini-study.
Because you say that the other games you tested exhibited normal behavior, I believe that the 'temporary change' you think happened could have possibly been luck?
But if you're really curious, take a look at the hex values somehow!
ncG1vNJzZmiapaGvorPAq5uepl6jsrV706GpnpmUqHymsdWenGaflaOxpr6Mq5itoZ9isKmtzaCcnWWkmrqxu9GaqaKkqWN%2FeoSSbW5o