E.g. Have a refuel interrupt that can interrupt others, and an interrupt that has 2 stops. If the refuel interrupt becomes valid before the train leaves the first station, then upon starting the refuel becomes active, and instead of the EXPECTED behaviour of just inserting the predefined stop(s) before the next station, the temporary schedule is wiped, and the interrupt is added.
This might be intentional, if so, make this VERY clear in the "Allow interrupting other interrupts" tooltip, otherwise (my preference) change the behaviour.
Single stop train interrupts would work, but then what is the point of interrupting an interrupt, if you cannot have the train continue where it left off? Why wouldn't I just use a normal interrupt with higher priority?
------------
Edit: Ignore this last section, pointless to the topic
Sidenote, to why this is an issue with my train network:
Dynamic train station names are not a feature. Thus dynamically dispatched pickup trains are only possible if you have every pickup station as the same name. (With wildcards dropoffs work as intended)
Problem: For n stations you need n trains because worst case scenario, every train goes to a different stop fills up, then waits until needed. Obviously resources that are not in demand will have trains sitting there uselessly.
Solution: Check if both load and unload have a space for a train, if so, do the obvious route. This train will occupy the train limit that very instant and prevent others from being dispatched.
However if you have for example both Plastic and Copper Ore loading stations open, have both stations named "Pickup", and need copper delivered, there is no guarantee that your train will actually go to the Copper Ore "Pickup" station.
With this system having two stop interrupts and an interrupting refuel interrupt, I've had a few cases of unintentional belt mixing, which is never fun.