CALCFIELDS in NAV2015

I have a weird issue. I'm trying to get a value from a calculated field, by using the 'CALCFIELDS' function.
When I run the table I can see the calculated value. But when I use the 'CALCFIELDS' function in a report or CodeUnit it is just not calculating. I ran the debugger and all that and no value. It's zero.
Any ideas what could be the cause?