(Some) Hops also contain amylase enzymes and are able to split complex sugars into sugars which can be fermented.
What happened is that in first instance my fermentation was slowed down, so I added the hop tea (made at 80° C, with wort, so no enzymes there) and the dry hop. I had some initial fermentation because the hop tea was made with wort (deliberately), but that stopped after a day or so, and then I put my fermenter in a colder place to let the yeast drop out better. I also plugged the airlock to prevent sucking in air.
The day before bottling, I put the fermenter back at normal ambient temperature. When I wanted to bottle, I pulled the plug, but after the initial pressure was released, the airlock bubbled faster than was possible due to only release of CO2 out of solution, and it kept up for about 24 hours.
Hop creep is not new, it is described in older brewing literature, and seems to have been rediscovered in the last couple of years, probably through the advent of massively hoppped IPAs.
It is also not consistent, sometimes it occurs and other times not, investigations (by scientists and brewers) are still on-going.