Different taste same beer

[Darren Jeory]

I have bottled 2 different beers half in glass flip top bottles and half in PET bottles...taste completely different. The plastic ones are really poor in comparison to the glass.

Anyone else experienced this?

 

[DavidDetroit]

While PET bottles seem to have a good reputation here (no reason to doubt it), they have a trick or two with the PET such as squeezing them to leave just enough air for carbing. If it's the same beer, very few variables (tight seal or light or, I suppose, flavor leeched from the plastic--I know you said PET).
Do you think it's oxygenation or too much UV or something?