Try making a copy of your project and stripping it down to the smallest deck that still exhibits the problem. Remove all the cards, scripts, modules, contraptions, etc you can, a few pieces at a time, until you narrow down the conditions of the bug.
In the process of removing things you might discover the answer on your own, and if not I can take a look at your simplified example. It's always possible there's some sort of bug in Decker itself.
Ugh, shit. The problem has nothing to do with zazz, or with your code; it's a regression in Decker. The contraption is bubbling its view[] event to the card (which should never happen). As a temporary workaround, add an empty view event handler to any contraptions which don't otherwise do something with view[]:
on view do end
Thanks for your help in identifying this issue.
I believe I have this fixed; the version of web-decker on beyondloom incorporates the patch, and it will be included in the next binary release.
