Raspberry IPA flavor changing

I'm a newbie on my second brew. I brewed a raspberry milkshake IPA before Christmas. After primary fermentation I moved to secondary with 3 lbs raspberry puree, the beer was between 2-2.5 gallons. I let it sit for about 10 days then kegged it. When I first tried it (5 days ago) after a week in the keg, I thought the flavor was really good. But I was having flow issues from the keg (this is my first time kegging), and I thought I was having carbonation/temp issues, so I messed around with temperature, changed to different psi, purged/recarbonated the keg multiple times. Today I found out that the dip tube kept getting clogged, and was interfering with the flow. I had to remove the liquid post multiple times and clean out hop gunk. Anyway, I tasted the beer today after I got a good flow, and the flavor has gone much more sour/tart. My question is do you think this was something caused by me messing around with things? Using too much puree for the amount of beer I had? I'm wondering if I let it sit longer if it will mellow out. Thanks for the help

 

Yes I would say more tart...it tastes just like it smelled coming from the can of puree (which is not necessarily bad, just different from the first few tastes). Unfortunately I started my "no drinking beer during the week" diet on the 1st. Hopefully this weekend I can go through some of it.

 

It did seem undercarbonated the first time. I had it on about 20 PSI for 24 hours, then 10 PSI for 6 days. But I was having issues where the pour was very slow due to the liquid line getting full of gunk, so I don't know if that was causing it to seem under carbed or not. But you may be right.