Difference in flavors between bottling and kegging?

Made a Belgian Wit with orange peel. Bottled half and force carbed half the batch in a keg. Any thoughts as to why I make have gotten very different flavors between the two?

The keg is very smooth, pleasant and easily drinkable. Whereas each bottle Ive opened has been very tart, almost sour. I use the same sanitizer for both bottles and the keg. I use Coopers tabs for carbing the bottels.

Any ideas?
The Dog.

I know dry malt plus beer can equal sour, cause we use it to sour our pre-guiness wort, perhaps the coopers tabs soured it... and if not by a ton just enough so you would notice because the kegged is so smooth? Have you always used these tabs? I use dextrose and just weigh it out and get pretty good results typically...

I think I was reading a threads not too long ago complaining about the carb drops. Not sure if it was inconsistent carbonation or flavor though.

Insufficient cleaning of bottles or perhaps stressed yeast once bottle conditioning took place?