How to get rid of the "invalid UTF-8 rune" error?

I get an error about “invalid UTF-8 rune” when I use grafana to display the graph of prometheus metrics. I add the variables for select different metric values, but some values contains invalid utf-8 characters.

It cause the panel throw an error “parse error at char 51: invalid UTF-8 rune” when I use “ALL” option.

I’m not care which the rune really is, I just want to display them. Is there any ideas?