That looks like normal water flowing mechanics to me from what I can see.
Water will seek out the nearest hole(s) in a 7 block range of source block and flow to it in a straight line and/or fan out. To fix that with the piston or so there, you would need to temporary wall the sides of the platform and then place the water and remove the wall blocks after it fans out.
Also the world is useless for we know not what mod versions or config settings you have.
Mods I'm running on the server is Forge 1.7.10, Galacticraft, NEI, Mo Shiz, Balkon's Weapons.
examples: http://prntscr.com/5qe26x http://prntscr.com/5qe49n http://prntscr.com/5qe4ym
I figured it might be a problem with my world so here is a link to the world download: https://mega.co.nz/#!RNtWlJgb!-f8RBDQ0pMEL9tlHZ1z6F2UZEjLfQl_jt9ZNN83auEg
Water will seek out the nearest hole(s) in a 7 block range of source block and flow to it in a straight line and/or fan out. To fix that with the piston or so there, you would need to temporary wall the sides of the platform and then place the water and remove the wall blocks after it fans out.
Also the world is useless for we know not what mod versions or config settings you have.
I replicated this in DW20 1.7.10 v1.0.3 pack.