Issues with pipes, mixing fluids

[Njk00]

Hi guys,
I have this weird issue where water or petroleum is mixed in the pipes, but they are not connected together. See the below picture:
https://ibb.co/86j5KK2

I'm very confused and I don't know where this is coming from. Any idea?

[Kalanndok]

They might have been connected together for a brief period of time. Just try deleting the water and see if it comes back. If yes, then you do have some kine of leak. If not everything is fine (for now)

[Loewchen]

If you can not find it yourself post the save and someone will find it for you.