The problem is that the hidden affordance for navigating the blog website interferes and becomes confused with OS and browser-level touch inputs. This happens on mobile as well as desktop when using a touchpad.

When attempting to pinch-zoom, many times the gesture will activate Blogger's hidden navigation feature, taking one to the next or previous post of the blog. On its own, the post navigation is activated by a swipe either right or left. (And your guess is as good as mine as to which way through blog history each swipe takes you.)

Occurs on: iOS/Safari MacOS/Chrome/using touchpad