If an alert is defined with a % in it's name, it is not possible to enable/disable from Settings>Alerts panel, or to click alert name in that panel to modify alert fields. Using workstation the alert can be edited and/or disabled. There are three alerts in the default SaaS management module that can't be disabled for this reason, e.g.:
Alert Name All Individual SGA Shared Pool Lib Cache Hit Ratio (%)
Alert Description Alert is triggered if ratio is below the expected range of the high 90 percentile in an OLTP environment.
If an attempt to open the alert is made the following error is displayed
This is a regression introduced in 21.6 APM SaaS release
Release : SAAS
Will be resolved in next release (21.9/21.10)