So if you try to spam Nami's laugh emote right at the end of the the animation it won't create the water splash. By the end, I mean just as she comes down from the 'jump' as her tail sweeps around, right before she goes into her idle animation. However, if you spam it before this point it seems to work just fine.
I was able to produce this the enitre game on TT. It was a custom game with just me and bots.

On a side note, her splash art isn't updated for the load screen or minimap art yet


Occurence: ~ 7/10

Steps:
-Pick Nami
-hit Shift + 4 (or whatever key you bound laugh to)
- just before it finishes , hit laugh again
-notice no water particles