How are you?
Coming back to Qlikview after so many days !
Though you don't think that Group By would be the cause(remember when you mention that, this may not be the cause- that means you say that - this may be the cause), still, may i ask you to post that specific code area or the application itself upload?
After reading your query the problem is not in Dimension Table.it is after Dimension Table.check it the Group by Script once.I have faced the same issue in my previous assignment.if you are applying Groupby in Transaction Tables with the Huge volume data.it will happen like this.check it once.
Thanks & Regards,