The activate view transition algorithm, in step 2, says to "set rendering suppression for view transitions to false".
rendering suppression for view transitions is a property of Document but the algorithm was neither given a document nor does it say which document to use.
This seems like an oversight and I assume that there should be a step similar to step 1 in setup view transition that mentions which document this refers to.
Noticed this while implementing the feature into Ladybird.