After upgrading UIM from 20.4+C5 to CU6 we noticed that Golden Metric views includes invisible data points (ghost graphs) when QOS includes recent data gaps.
This is also seen in Metrics View set with 24 Hr Time Range and Aggregation Interval set to Raw.
This is similar to a defect that was resolved in CU4, DE536215, but is back with CU6.
UIM 20.4 with CU6
Known problem with CU6
The fix for this issue will be included in 20.4 CU7 release.