Often times when swap offers get taken, it's split up into LOTS of small ones, like this (this goes on for another whole page):
[snip]
What's up with that? Kind of annoying.
From what I hear, when the swaps backing a position expire and new ones are taken out, if it's already fragmented, the fragmentation is maintained - the engine doesn't see a position backed by 3 $500 swaps ending simultaneously and decide to open a single $1500 swap as a replacement, instead taking out 3 new $500 swaps... which most likely creates new fragmentation as multiple swaps are taken to fill out each of those $500 chunks. The longer the position is held for, the worse it gets, with more and more tiny fragments created which can only be coalesced by the trader closing out their position and starting over.
So that process of ever-increasing fragmentation has eventually resulted in the fuckery seen in your image... so far as I can tell, the best way to try and avoid it is to have your swap offer taken as one of the last of several taken together (i.e. place your offers so that you're never the
very best offer, but instead have a couple below yours to act as a buffer - let them get fragmented so you don't have to). But that's by no means foolproof, and may just be superstition on my part.
The actual best way would be for 'finex to fix their engine so it batches together swap-requirements so as to recombine fragments where possible, but I don't know the implementation details to really know how difficult that would be.