On Minitest debugger error no line number or click on link to take you to line in code missing (RESOLVED)

Previously when an error occurred during a test unit run a clickable link and line number would appear in the console output screen.

This link would take me to the line of code the error was triggered.

This link ha suddenly disappeared. This is causing a lot of wasted time finding the error cause.

I get the error , eg Minitest::UnexpectedError: NoMethodError: undefined method `slug' for nil:NilClass

But line number or link to the code is missing

Tested on 2016.3 and 2016.2

Thoughts?

TIA

Geoff