There has got to be some sort of problem with the way the variable rate is calculated (unless maybe 90% of all loans are variable) as the rate has now dropped to 712% on a <$2000USD loaned difference...
If there is truly nothing wrong with the calculation, I strongly suggest traders stop using variable rate loans as you can really get screwed by small amount of USD lent at very high rates it seems.
I think the effect is really insidious.
I don't know if I'm missing out some feature here, but as far as I know, you can't control the loans you pick when opeining a trade. The only other possibility is to borrow beforehand, which works, but is tedious. Thus, basically if you just have some market or limit/stop order placed, you get the "best" lending offer.
Now, yesterday a huge pile of VIR offers were on market, thus you allways got the VIR loans first. They were cheap, thus no problem. But now you're holding a position based on a VIR offer, and now the VIR rate shoots through the ceiling. Just because some traders accidentally take one of those exaggerated offers. These really poison the average. Especially when those lenders offering for fixed rate cancel their offers and place higher offers instead. This way, a tiny fraction of the offerings can influence the whole lending market.
Actually I witnessed this happen. When I came back, almost all of the fixed rate offers were gone. Only one $400 for 1 day at 40% and about $6000 at VIR were left. Then, during some minutes, my swap literally counted up. First I didn't even realise what was going on and thought this was a technical problem, until I looked on the order history and lending page and realised that one of my limit orders had executed and I had gotten one of those poisoned offers.