[0.17.11] Strange Robot Paths

[dankellys]

I am having an issue with bots and think it may be a bug. Basically, by bots are picking up blue belts in my mall (blue circle on bot_path.PNG) to the north of my base, then flying all the way down to the southern perimeter wall (red circle), recharging off a roboport down there, then flying all the way back up to the north to place the belts in a blueprint I have place (purple circle).

Screenshot example of their path (bot_path.png)
Screenshot example of bots at the southern wall, carrying blue belts (bots_southern_wall.PNG)
Screenshot of Mall (mall.PNG)

As you can see from the screenshots, there is some deconstruction going on down there, but these bots dont appear to be involved in that, they are literally flying down with blue belt. Stopping to charge, then flying all they way back up again

Not sure if this is a bug, or if it is something going on with my specific base...but I have checked and cant see any reason why they would do this.

[TruePikachu]

What goes in those chests all the way at the wall?

If you can reproduce this, please upload a save.

[dankellys]

The chests are buffer chests for pipe, underground pipe, flamethrower turrets, walls and laser turrets to help with maintaining the wall defenses.

Save attached.

EDIT:
The buffer chests are actually requesting blue belts (not needed anymore, but its from an old blueprint where they used to be needed), however, this still doesn't explain the issue. The bots aren't depositing them there, they are flying down, charging, then turning back

[E-37]

Ive been having the same issue since 0.17 launched. If bots are trying to fly to a very distant destination with no roboports directly along their path, they will just fly straight there and then run out of battery part way there. They will then just turn around and limp back to the same roboport they started from, recharge and repeat over and over again. They never reach their destination unless you build roboports along their path.

[TruePikachu]

This "limping" has been an issue for as long as I can remember, even in 0.12.

The main question here is what robots are doing at the south wall; it's hardly the closest roboport, so my theories are either (a) a miscoded new functionality that directs robots to unused roboports or (b) some interaction involving the buffer chests at the wall.

[Rseding91]

I think I know what's happening. At some point you had the items needed for the construction job at the north end of your base available at the south end. Robots went down there to grab them and started on their way back north. They ran out of power on the way and turned back around to charge. Meanwhile the same thing happened in the opposite order for robots in the north: the south requested items and robots in the north went to bring them south. They also ran out of power and went back north to charge.

The root of the problem is: you've built a non-rectangular roboport network and robots simply don't work with those networks.

Fill in the gap between your south and north base and the issue will resolve itself.