When adding a URL Label to the Hyperlink column on a Straight Table, the result set will return blank or Empty values.
June 2018 IR, June 2018 Patch 1
Sept 2018 IR, Sept 2018 Patch 1
This has been addressed in Qlik Sense February 2019. See the relevant Release Notes
for details on item QLIK-91670.R&D Comments: This is a problem that's currently in the product, but as long as you have a table with a url created before the June 2018 release and don't remove the URL label expression it will work correctly. If you in June 2018 or later remove the entire expression and then later enters the =Num expression it will failWorkaround:
Adding a measure like =Count(FieldName)
or just a field =FieldName
to the table solves the problem, but that will not be a good practice and not suitable for certain scenario.