I stumbled over a weird error on one of my collected traces where out of the seven span's all are expandable except one. 

When clicking on that particular span JS console reads an Error

Cannot read properties of undefined (reading: map) 

The Screenshot of that occurance and the trace causing it are attached.

I am not sure if this is a UIPlugin issue or something that gone wrong in the trace itself but Grafana can render the content without any problem (just as reference)