two same carriers on one road part

[SimonHeimberg]

Describe the bug
Sometimes I get two carriers (first carrier type) on the road, one is sitting doing nothing, the other is working, even if there are multiple wares to move. And sometimes they work together.

One carrier just sitting around on the road does not really harm, but it is at least strange.

To reproduce
To reproduce the behavior:

It often happens when a road is split by a new flag while its carrier is walking on this road. Quite often two new carriers are sent to this road then and the old worker retires on his road. The old carrier may be walking for the first time to the middle of his road (still arriving), or he may have been carrying a ware or may have been walking back from carrying. Not totally sure about the conditions. When I try to force it, it works for maybe 70% of my tries.
It also happens for the ai player. Easiest to see when its starting condition has several buildings. (You need to be a team mate or play without fog. )

Expected behavior
One carrier of each type on a road part (between two flags).

Replay
Will follow ...

Version:

• OS: Debian 12.0, flatpak
• Widelands Version: v1.1

Additional context
Mentioned in forum thread 5662

[SimonHeimberg]

The replay, both files in one zip:
Lake_of_Tranquility__2workers.zip size: 55k

After 40 seconds, two blue carriers leave the HQ for a road being split once only. So one will join the previous carrier on the middle part.