That timing seems to be expected. It may just be due to how AirWave communicates with IAPs to push changes. Here's an example of the interaction:
1) VC checks into AirWave, sees no changes
2) AirWave has setting change to rename IAP
3) VC checks into AirWave, sees there is a pending change
4) VC pushes the change
5) VC updates AirWave
6) AirWave runs an audit to confirm changes
This timeline of events can be seen in /var/log/ap/<ap id of AP having name change>/event.log (may also want to see the VC's event log as well). It is not an instantaneous change, so timing will vary based on when the VC checks into AirWave.