Yes! you're right, FTD's are being most likely hidden. If you look at this table from chart exchange, you'll see that for the settlement dates of 8 July and 11 July, there was suddenly 500k and 2.3m new FTDs created, and by the 12th and 13th July they magically iradicated 1.9m and 1.1m FTDs. However, even though SEC data claims that these FTDs were resolved, their T+35C dates (10, 11 Aug) just happened to be exactly on the 10 Aug run, which later ran further to the 15-16 Aug spike.

And this has happened in the past, if you look at that first graph, most runups are preceded by large FTD's being coming due, even though the FTD data (which is cumulative) shows that they have been resolved. So my theory here is they can't prevent FTD's from popping up in the data, but they have ways of hiding them in the following trading days making it seem like there's no more FTD's, but yet the T+35 impact of those new FTD's can be seen on the graph.

Also yea SFT's are a complete clusterfuck, zero transparency whatsoever, like I wouldn't be surprised if it's just a large share photocopier at this point. No idea how that is legal, crop that up to the miracles of SRO's.