I'm travelling daily from Hampstead Heath on the London Overground to
Canary Wharf over Stratford thus in zones 1 and 2 only. The oyster
PAYG fare is normally £1 since it covers zones 2+3 only.

I noticed that when I change to the DLR at Stratford I am charged £1
for the journey but when I change to the Jubilee line at Stratford I
am charged £2 for the journey.

Why is the Jubilee line charging more than the DLR even though I am
traveling on the same route in the same zones 2 and 3?

Thanks