I don’t know if this is an actual bug or it is like that by design.
The “Release Notes X.X.XX” page that appears sometimes after an update is not zoomable.
But you can switch to another tab, zoom in/out, move back to the Release Notes and find out it has been zoomed in/out.
The “Release notes” aren’t actually a note, they are a webview pretending to be a note in a tab. Last time I checked find didn’t work either.
Moved to help for now.