Pineapple pilsner flavor. Fermintation Question

Here's the story: I used a White labs pilsner yeast and pitched at 70. After fermy started I put the carboy in the fridge and let sit for 2 weeks at 50 - 55. I then gave the carboy a swirl or two and brought the temp up to 70 for about 36 hours. Fermentation started again and a new krausen developed. As it had been over two weeks I racked to a secondary and then lowered the temp to 38 to lager. The beer tasted like pineapple and the hydrometer read around 1.02. After about a week in the secondary at 38 I brought the temp back up to 50 and a new krausen has started. Can anybody explain what is going on? Will it lose that pineapple flavor? How long do I let it sit again at 50? Seems like primary ferm never completed. Will beer still be ok?

I've had ferments restart after a period. I have a Brown Porter that fermented to 1.020 in 36 hours, sat for almost a week, then started fermenting again and is still going 10 days later.

The pineapple should fade.

I'd recommend not pitching so warm next time. Try getting it down to fermentation temps before or at least immediately after pitching. That's where the fruit flavor is coming from.

Brewing a pilsner right now myself.

It has been my experience that tasting a pilsner mid brew is no real indication as to what it will taste like finished.

Usually there is a lot of sulphur taste even when fermentation is done. I have bottled 2 batches but intend to put this batch in a keg (new kegerator on site). It usually takes 5-6 weeks for it to condition in the bottle. I have heard some discussion that storing it in the fridge (as opposed to room temp) will speed that process up, can't vouch for the validity of that statement though.

The longer it sits in the bottle, the less sulphur odor/taste, the better the beer. I think the general rule of thumb for lagers is that they are slow and take way more time than recipe time-frames suggest.

Bobby has it right. Warm temps when you pitch your yeast will result in a fruity lager. How much of that flavor you get, depends on how long it is at the warm temperture on the start of respiration and fermentation.

I'd not sweat it.

Firerock pale ale of Kona Brewing Company has a residual hint of pineapple due to fermentation caused fruity esters... it's pretty decent for a pale ale