Mine tend to wander a lot before/during/after splitting...
I think I had a three way split last night... Woke up to find 3 nem's in the overflow... Luckily my new "nem stopping intake tube" seems to have done it's job, but I had fun fishing 'em all out and putting 'em back in the tank proper!
I had a HUGE Green BTA than wandered into the rockwork one day, and I didn't see it for over a year, then one day this TINY lil' pitiful GBTA wandered back out into the light... It's bigger than a large dinner plate now...