BTC swaps are getting manipulated, its pretty obvious. The amount of swaps really getting shorted is probably 50% of the amount being shown.
Someone or a group of people are reserving, but not using. Most likely to force interest rates much higher. Up till around a week ago only around 8k was actually being used/reserved.
I have to constantly scan swaps now for cheaper rates so I don't end up getting killed by high rates.
Someone figured out how to do this with the USD. I think the bug was that you could reserve for less than one hour before you were charged interest. The person/group would reserve 1-2M and let the rate rise. Before the hour was up the reserve would be returned and then it started all over again. It showed itself by 1-2M in swaps being taken and then being dumped back approximately one hour later. Are you seeing that with the BTC swaps?
Bitfinex fixed this quickly once they were told about it. I doubt it, but maybe they didn't apply the same fix to BTC. You might want to go directly to support with your concerns.