Not sure why or how it is happening, but for some reason Chrome is marking any of these events as "active". The actual message looks like this:

[Violation] Add non-passive event listener to a scroll-blocking 'wheel' event. Consider marking event handler as 'passive' to make the page more responsive.

We're using a 3rd party library (along with d3), and with one particular test case this happened twice in the same page: one 32 times, and one 360 times.

It looks like this applies to both version 4 and version 3.