I use dedicated slots in trains (Freight Forwarding's Cargo Ships) so many different item types can be inserted. Usually, inserters use "waiting for train" special condition when near train station, but since ships are LARGE they require usually pretty long inserters to operate. The inserters located farther than few tiles ignore the train stop condition and grab any item they can grab as soon as the train leaves, thus deadlocking themselves if this item type is either cannot be inserted to the train or is not consumed.

See screenshot for details (the right-most red inserter is causing the problems).
https://disk.yandex.ru/i/o4lhHaODb1RZiQ

The ship already has red ammo container and no more can be put.
https://disk.yandex.ru/i/qH3YnoNzaNgOhg

I've tried setting up condition for checking if there is a train on the station (T != 0), but there's 1 tick delay in which inserter happens to grab an item.

Also, this may be related, when you change inserter settings, SOMETIMES it doesn't recognize the objects it should interact with (highlighted with white box), and only rotation (or sometimes only deconstruction & reconstruction) can fix this.

This mod does not affect how inserters operate, It only changes the way they're configured, what you want Is to prevent inserters from taking items when ther's not a shop there.

You should ask this to the author of the cargo ship because this Is a vanilla mechanic.

This mod only operate in changing the pickup/drop Vector does not do anything on_tick

The copy paste setting also Just filter wich setting you copy from inserter to inserter but does not changes its functionality.

Hmm, you are kinda right.
I have found that the reason this happens is the HUGE interaction box of cargo ships while the inserters are normally defined to work with only the 2-tile-wide trains. After I increased the drop point it started working as intended.

@Wip-Sama, any ideas on that?

Also, this may be related, when you change inserter settings, SOMETIMES it doesn't recognize the objects it should interact with (highlighted with white box), and only rotation (or sometimes only deconstruction & reconstruction) can fix this.

I've found some cases when inserters were not working unless you rebuild them with the exact same settings on the exact same spot.

In trying to reproduce the problem, but I could not make that happen till now, the sometime behaviour is really strange.

The only think that come ti my mind Is that MAYBE the cargo ship mod does something to make that White box available, so It interact with some events and an action tht you do dies not trigger that action.

My mod does not send any events that I know of when changing inserter pick/drop position.

In trying to reproduce the problem, but I could not make that happen till now, the sometime behaviour is really strange.

The only think that come ti my mind Is that MAYBE the cargo ship mod does something to make that White box available, so It interact with some events and an action tht you do dies not trigger that action.

My mod does not send any events that I know of when changing inserter pick/drop position.

OK, I'll find the way to reproduce it without any other mods and file another topic.