Is it possible that you ramped temps up too soon, before at least 50% attenuation?
This method works, but you need a properly pitched and clean ferment at lager temps until your get beyond the 50% attenuation mark before ramping temps up to ale temps to finish out.
I think that could also be a possibility. I checked gravity a day before ramping up and was at 45% attenuation, so I figured I'd be good a day later. Yeast I pitched the recommended 1.5 M cells / ml / ° P, so I should be good there. I will say that even on the other beers I've done with the method I've been generally happy, but was not ever 100% happy with it. The next time I might wait until 60% attenuation to ramp up and try to ramp down a little more slowly.
I rushed this batch more so than others I have done using the method in order to submit it in time to a competition (which is idiotic now that I think about it, rushing a beer and thereby making it lower quality in order to get it judged). I'm not writing off the method, I think I made some mistakes and try to push it too far.
I do think that the idea that the beer is ready and perfect right after the D-rest is not really accurate. I think you need some cold conditioning for at least some time (maybe a week) if you really want clean tasting beer.
I'll find out in a few weeks how the beer fairs in competition. I submitted it to two separate ones, one at the end of April and the other the first week in May.
I plan to brew two helles simultaneously in about a month and will use this method again, with some more care this time. Again, this was the 6th or 7th time using this method, and I admit I rushed it a bit.
EDIT: I may make another starter of WY2000 and pitch it into the keg and allow it to lager for a week or two to see if that remedies the situation.
EDIT 2: Just saw that WY2000 flocs out at 37 already, so maybe my problem was the quick ramp down (pretty much dropped it in two steps), that didn't allow for the yeast to clean up.