How to fix the Google Analytics gtag.js Low or 0% Bounce Rate

When using the new Google Analytics gtag.js and sending custom dimensions or metrics as events you can see a 0% or very low bounce rate. Something like:

That might look unusual low, so in most cases it’s a bug. In my case it was caused by sending a local_dimension or metric:

gtag('event', 'x_dimension', {'x123': 'variabletext', 'y456' : 'variabletext'});

It’s caused by not adding non_interaction mode in this event:

{'non_interaction': true}

So in total it becomes:

gtag('event', 'x_dimension', {'x123': 'variabletext', 'y456' : 'variabletext', 'non_interaction': true});

Hopefully this fixes it for you as well. More info on the GA Docs.