This issue only occurs when the device is in offline mode (with or without SIM) and is switched off and then switched back on (with SIM). During this start up the user is asked if the device should continue in offline mode. When selecting no the device initiates a profile change from offline to normal mode. During this process the intro sound is muted.
The settings must be: Menu > Crtl.Panel > Settings > General > Personalisation > Tone > Warning tones > ON