platform grouping

Option to combine platforms. (No not the grouping, read-on :-) )

From what I've seen, I think a destination is choosen and frozen even before a train leaves the source station. Therefore when arriving at destination with 100 unloading platforms with the exact same setup, and connected to the same final storage, it will wait specifically for the platform it had choosen when it took off (or earlier). The train HAS the switches available to go to the other 99 platforms....
Replace 100 with 2 and 99 with 1, because of economic and room constraints; your train will sit there until the one on the hard coded destination platform left.

Yes, you can work-around the problem by setting a "number of trains", but that is a work-around; if you set it to more than 1 you have the same issue! Trains will not reconsider their drop-off platform.

So pretty please, either with name or a tickbox for "shared". They should only reconsider if both that "shared" box is ticked and if they are within a train length of shortest open path first away from the platform and the platform is identical either or both in name and/or platform layout with uniform material delivery.