Trains not filling up to the max

Happened a couple of times already (first one with Coal)
The train arrives at the designated station, it starts to fill up, but leaves before it is completed (see screenshot)

Others have reported the same issue on Discord

Related + save https://discord.com/channels/803508556325584926/883590993063051275/1498325170765430795

Here is my save for likely same issue. The save is already focused on the relevant train station and the train will arrive in 20 seconds. Steps to reproduce:

1 - Open station panel, and observe that the train has booked 1440 sand to carry.
2 - Train arrives at 20 seconds, starts loading. The station is fed by T2 belt, it can't keep up with the loading speed. When station inventory of 240 hits zero, the train moves one wagon ahead. Keeps repeating this until all wagons are tried.
3- Train leaves the station with 384, 52, 52 sand in each wagon, respectively. Carrying only a fraction of the initial booked amount.

This happens exactly as described, but I don't believe it's a bug. I think it's just unexpected to see on networks (and they don't have a "wait until fully loaded" departure option).

Perhaps the devs would want to add a "Wait Patiently" or "Load Fully" button to stations similar, to the "Fully Unload" button lines have? Perhaps it adds a five second delay after the station empties before the train leaves, so a station being fed slowly will force the train to wait.

Or if not, maybe add an alert to that train, like the "your train failed to load fully at its previous station after reaching a fork" alert.

From my point of view also is not a bug.
You are using network and probably the target station does not allow to contain more than the train loaded.

The reason I called it a bug is because the train makes reservations in both source and target stations for max amount of materials. You can see here it reserved 1440 sand in target station. Reserves the same amount for source station too. But in the end only delivers 488 sand.

An the source station have the red bar full on right or also in the middle?

This is the source station. So it is in full push mode and has an active reservation.

We are working on a fix, "low" throughput seems to be the cause.

This will be fixed in the next patch

encountering the issue again: my 2 wagon train fills the first one, then the remaining 2 are left empty, but plenty of ore in the station
Was the patch applied?

If it is a network train it might be because the recieving end does not have room for a full load