"cannot mix different fluid" error not triggered if unpowered

[CzBuCHi]

vanila game version: 0.18.36

how to reproduce:
1. place chemical plant
2. set recipe, that uses differnet fluids
3. connect plant inputs - game will not throw "cannot mix different fluid" error

i think, it is because pipe is empty and chemical plant input do not 'lock' pipe to specific fluid when connected

[boskid]

Not a bug.

When simplified fluid mixing check was implemented, Rseding explicitly decided to only check fluid in pipes and fluid outputs from crafters since they can inject fluids into pipes. Inputs are not taken into the check since they can at most take fluid.