Help:Property annotation health
Property annotation health (coefficient between proper/improper values assigned) indicates how well "correct" values correspond to a property description. For example, some improper value annotations can be caused by a type change or an alteration of allowed values assigned to a property.
The health factor can be improved by checking the Has improper value for property list and correct those mentioned property-value pairs.
Special:Statistics count discrepancy
A discrepancy for the Has improper value for count (compared with the actual Has improper value for list) displayed on Special:Statistics can be caused by a long cache expiry, missed job updates, or delayed refreshLinks update (required when template are involved)
It is suggested to run rebuildPropertyStatistics.php on a regular schedule to adjust for possible discrepancies.