Partition object named

EmpCount = CALCULATE(COUNT(Employee[EmplID]),FILTER(ALL('Date'[PeriodNumber]),'Date'[PeriodNumber]=MAX('Date'[Period])))

This expression refers to a Partition object named 'Measure[Measure-a91b4ec5-62d6-4f10-91b4-0d128eb4f4bd]', which has an error.