Which build of XBMC/SPMC/Kodi do you have installed? Check under the System menu, click the System Info entry there. It'll mention the version there, see one from a Windows install below.
If you click on the System menu itself this time (after closing the screen above) then head to services, you might want to check if AirPlay has any options to play with there.
Which Apple hardware are you using, and which iOS version is installed? From which app(s) are you using AirPlay for videos. We don't have iPads or iPhones in the office, but it may be another customer can compare their settings/experience with yours.