In a rare condition flows may be dropped by NPM even though the APM is in "Active" state.This article covers a rare condition, where the new flows may be dropped by NPM with "Load-balance failed" reason. Following has to be met in order to qualify for the Solution in this KB Article:
The cbsflowagentd daemon (normally running on all VAPs) is responsible for reporting the utilization of the APM to the CPM. If this daemon isn't running, balancing new flows to the VAP will fail.
The issue has been addressed in XOS V10.0, V9.6.8 and V9.7.3: