Nope, maybe a fake master with empty values?
This could fit Custom Block - Discussion - As you could have a string value variable to avoid this problem.
Also, I think this error is bad, cuz it throws an erroneous error message that might confuse users who don’t have a full idea of their dataset. We should improve it. @dmai @hardik
In this case we should throw an error like “the value variable returned empty value”.