I was tearing down some roads whilst a carrier was carrying a trunk. Usually this causes the carrier on the torn-up road to return to the nearest warehouse. In this case the carrier will walk to the new road but will not put down the carried ware.
In the attached replay, fast forward past the two fortresses being built and inhabited. A barracks will be built to the south-west of the area and then inhabited. Afterwards watch the third trunk produced by the lumberjack to the south of the barracks. As the carrier with the trunk walks on a road, it is torn down. He then walks towards the HQ carrying the trunk. Just as he walks to the first flag on his route, a new road is created from the flag, causing a carrier to be requested. The rogue carrier is sent to this road, carrying his trunk. When he is next required to transport a ware, he will put down the trunk on a flag and then both carrier and trunk act as normal.
The abnormal behaviour is not blocking but I thought it would be worth reporting in case the cause triggers other problems.
Setting to incomplete for bug sweeping.