mobile browsers fail "Media query screen height" even though expression = desired expression & actual value = desired value. What does this mean?

[namesarebloat]

Maybe this makes sense, but if so then that's not obvious to me from the information provided.

From Mull and Tor:

expression: undefined desired expression: undefined actual value: undefined desired value: undefined passed: false,false,false,false,false

Interestingly they pass screen width despite (or because?) actual value differing from desired value

expression: undefined desired expression: undefined actual value: 980,980,980,980,980 desired value: undefined passed: true,true,true,true,true