Hello =)

Not sure if this is the right place to report the dupe but i will give a try^^
You take some fluid into reservoir and pickup some stone tanks for example. the tanks stack and then set reservoir to 'refilling equipment' mode with sneak+rmb. then you place the stone tanks in the world and every one of them gets the fluid from the reservoir.

Check this video to see what is the problem =)

https://streamable.com/nbros

Minecraft: 1.12.2
Forge .2708
Modpack: My own Modpack: Dungeons, Dragons and Space Shuttles

This issue page is where you can post everything about this mod and that bug was caused by this mod.

Fixed in 3.9. Thank you for your reporting.