That's a weird one - 200000% is a bit higher than I would expect

It was flying for a while there, though. I might have a bug where there is a missing decimal point and it should be 2.00000. Let me know if you see it with any other ones.
The short loans, though, happen all the time at high percentages. Pololen will try to lend them, of course, at a super high rate. My record is 1.8% which lasted, maybe, 8 seconds. As soon as there are lower loan rates available I *think* Poloniex will close the existing ones and give the trader lower rates. That's only a guess though. I know that they can find lower rate loans for traders under certain circumstances, but I don't know what those circumstances are.
Or it could be the trader saw the loan rate and immediately closed their position. I know I would

Wow, what a Dev !!!
Did you read my brain ? ;-)
I'm sure you are very experienced in Polo lending, and you got even a better insight with your tool too.
I'm lending quite well between 0.2 an 0.37 and would like to keep it up there, till I know it better ;-)
Why can I see a booking in my "recent closings", where I lent 0.01 BTC for 11 seconds at 200000% ........... don't forget to blink ;-)
Where does that come from ?
Looking forward for the new release, thanks mate :-)