I made an oil setup with everything except heavy oil voided, and once it got full and all other liquids were voided, the mod would error for trying to set fluid to a non positive value. I lost the error message, but I hackily fixed it in my local version by wrapping the call to pipe.fluidbox.flush in control.lua in a pcall. So it's something with setting the fluid amounts to a value it shouldn't when everything is empty. Error only occurred after a few minutes in game with it there.

Have gotten the same error 2 times in probably 15 hours of play after using the void pipe in a way similar to GreenScripter. Here was the only output:

The mod Fluid Void Extra (2.0) (1.6.0) caused a non-recoverable error.
Please report this error to the mod author.

Error while running event fluid-void-extra::on_tick (ID 0)
Fluid amount has to be positive.
stack traceback:
[C]: in function 'flush'
fluid-void-extra/control.lua:81: in function 'processPipesWithSpeed'
fluid-void-extra/control.lua:66: in function 'processPipes'
fluid-void-extra/control.lua:33: in function <fluid-void-extra/control.lua:32>

Hey, sorry for the incredibly late reply.
I was not active in Factorio or modding for a long time.
Updated the mod today.

I am not sure if this specific problem is fixed, but there was an error in the code, where it supplied the fluid instead of its ID.
If this is not working, I will have to check for something else.

Is there a way to reliably reproduce this error?