Great Western Coffee Shop

Merry Christmas everybody.
Just saw on RTT that the London Paddington-Carmarthen service is terminating at Swansea due to an operation incident. What does an operational incident actually mean? What could have gone wrong?

Also reports
from https://wiki.openraildata.com/index.php/Delay_Attribution_Guide

Something to do with having to take the whole 10 cars into Maliphant at one go?  Perhaps lack of shunt staff later on when the five on to Carmarthen got back?

I suspect that "operational incident" is often code for various various types of "own goal" that the railway do not wish to give details about because so doing would make them look [even more] silly.

Examples could include, Sending a driver without the required route knowledge to complete the journey, perhaps forgetting to arrange relief en-route.
Sending an electric train for a route not electrified throughout.
Failing to unlock the station in time for the first train, or locking it before the last train.
Forgetting to refuel a train.
Forgetting to book road transport.

My guess would be that they've put a 9-car unit on it and still not moved the starter signal at Carmarthen about 70ft nearer the points.