In multiplayer, filter miniloaders have their belt lanes swapped.
Left lane filter outputs on the right lane, right lane filter outputs on the left lane.

Mods: https://hst.sh/sihegayida
Save: https://drive.google.com/file/d/1gKYkApizJsgJxn3v6Lrw3u9wWLiOE5r_/view?usp=share_link

Additionally, we believe this started happening after we disabled the Inserter Fuel Leech mod.
Inserter Fuel Leech: https://mods.factorio.com/mod/InserterFuelLeech

Seconded, this just happened to me for a second time after adding another, totally unrelated mod to the server (in this case being ModuleInsertersSimplified).

I definitely think this is a bug, and quite a major one - hinting at a faulty or improperly stored configuration for the miniloaders.
I'm thinking of deeming their split lane configuration to be too unreliable to really use, which is quite a shame as it's a really helpful feature!

There are also cases where the bug fixes itself, but then breaks again.
We've never seen this happen in person, but it is easily evident by some factories stopping production due to belt clogging because the lanes switched to their correct side and then swapped back to the wrong side some later point. We suspect this is caused by the game still running for a short time after all players leave the server, but we have no way to confirm this as it happen inconsistently.

It's a bug caused by wrong entity order: https://github.com/mspielberg/factorio-miniloader/pull/72 . For now the only solution to that is go to https://github.com/Janzert/factorio-miniloader/tree/update-split-filters , download these files and pack them into a mod file. I've used it before and it is stable even when changing the mod list

It's a bug caused by wrong entity order: https://github.com/mspielberg/factorio-miniloader/pull/72 . For now the only solution to that is go to https://github.com/Janzert/factorio-miniloader/tree/update-split-filters , download these files and pack them into a mod file. I've used it before and it is stable even when changing the mod list

The fix works great, no switch overs and can freely change mods again. However, if you are playing Space Exploration, it will cause a non-recoverable error any time a Space Ship launches. It seems to be an issue in the clone function. I had to revert the change as a result unfortunately.

However, if you are playing Space Exploration, it will cause a non-recoverable error any time a Space Ship launches. It seems to be an issue in the clone function. I had to revert the change as a result unfortunately.

Getting back around to factorio again and thought I'd look into this, but so far I've been unable to reproduce the error. I've tried with satellite rockets, cargo rockets, and the actual spaceships with miniloaders on and off the ship. Possibly some change in SE has fixed it in the meantime, but that seems unlikely. Do you have any more details on what might trigger the problem?

Changing the list of enabled mods is the cause afaik.

Yes, that is one way to trigger the lane swapping bug. Which is what my patch is meant to address and works well for me at least.

But in that last reply I was actually talking about trying to fix a crash DrP was seeing while using that patch with SE.

Ohhh

This should be fixed in 1.15.7.