In ArcGIS Monitor 10.6.1, new metrics were introduced for the Portal counter type. Some counters were renamed and moved to a tab structure. This was changed to improve the usability of the software's interface.
As a result of these improvements and design changes, the number of Portal counters appearing in the left panel tree view is reduced. In addition, the renaming and changed structure of the counters prevent matching and use of the historical Portal counter names previously in the tree view in ArcGIS Monitor 10.6.0. For this reason, the Portal counter names in 10.6.0 are not visible in the tree view in 10.6.1. Instead, refer to the new tabs illustrated below for the Portal metrics.
The following screenshots illustrate the expected Portal counter names in 10.6.0 and 10.6.1.