Factorio Forums

https://i.imgur.com/mJQiouu.png

Savegame attached. The highlighted pipe has petroleum gas in it and I can't tell where it came from. That pipe network only ever has heavy oil. I feel like I've followed every connected pipe repeatedly and can't find where it's coming from. This is the third or fourth time it has happened. Each time I remove that pipe and replace it, and it happens again after 10-30 minutes.

please upload the mods too

mods attached

Unless you have some save where it's heavy oil then it switches to something else I'm going to say at some point you're mixing pipes because I've never heard or seen anyone have this problem before.

I bet you accidently misplaced the underground pipe above the chemical factory connected to petroleum one tile more right.

This happened to everyone some time.