Factorio Forums

I was making and trying concrete (and not having enough so got like 270 of that gear alert)

In the meantime I bots were working on defenses and one of the flamethrower pipes got too long and shut down, after wich I used super force build to put a new pump in (the system exclusively contains flamethrowers With one underground pipe between them)

a bit later, all underground pipes lost collision. I don't know how to put images ore vidoes in a forum post (I used that new steam recording feature for a video) so ican't show you but I could just walk through their entire sprites (I know you can squeeze in between them normally but then they still have collision). This was only a problem with undergrounds, normal pipes were unaffected and I haven't checked with pumps. I did a save-quit and was not solved that way (I don't know if my bots finished that force-build yet). Also I don't have the expansion (I want to get no time for chit-chat before I do that).

also I play vanilla

Hello, thanks for the report.
As of 2.0, underground pipes intentionally don't have collision with player to make it less annoying to walk through fluid processing sections of factory.

Thanks for clearing that up so fast!