Pakistan won two Tests in 2016 on flat London pitches (Lord’s and Oval). Since 2001 Old Trafford Test, because has been trounced in every single non-London Test, which are traditionally more bowling friendly with the classic English conditions.
The 2018 win at Lord’s was an anomaly. England lost because they picked a weak team, with Stoneman opening and Malan batting in the middle-order.
They have a stronger side now and Pakistan will be whitewashed this summer. Anyway, carry on with the celebrations until that happens.
I will say it now - Pakistan’s days of being England’s bogey team are over. In fact, it would have been over in 2018 as well, but we were lucky it was only a two Test series.