Our SSL Certificate had SANs for the host and the IP so don't think that could be the cause.
The release notes for 8.2.10.1 explicitly mention a fix for this issue so I assume it is working now. We have not needed to perform a firmware upgrade since applying the 8.2.10.1 update, so I can not confirm it is fixed yet.
DE33622: After an upgrade to AirWave 8.2.10 and CentOS 7, AirWave failed to complete an IAP firmware upgrade after sending firmware upgrade files to the IAPs. This issue is resolved in AirWave 8.2.10.1.