I just built a new SP 2013 farm using Office Web App RTM, SP1 and then the November 2015 CU (KB 3101367) .
Control Panel is still showing that the OWA version is 15.0.4571.1502, which is for SP1 not the November 2015 CU.
Powershell (Get-Content C:\programdata\microsoft\officewebapps\data\local\officeversion.inc) is returning the correct version 15.0.4771.1000.
Rebooting the servers does not make the Version number in Control Panel change.
Has anyone else seen inconsistent version numbers like this?
Is this something that I need to worry about?
Have you tried, exporting your OWA configs, and then uninstalling and reinstalling your OWA Servers and farm?