Thank you for that. From my investigations so far, what seems to be happening here is that the status of the stop is updated only periodically, and it is the status that determines whether it is overcrowded. It is intended that it be allowed to exceed its stated capacity by 32 units of goods, but I can see excess here by several hundred. The reason for this, I think, is that the large number of farms nearby all discharge their wares into the stop before it registers as being overcrowded.
That was formerly compounded by goods in transit not counting towards overcrowding, but I have now fixed that latter issue. What you will notice is that, once it becomes overcrowded and registers as such (red status bar), no more goods can be added until it drops below the level of being overcrowded again.