Distorted message sound on iPhone

Chances are, the Alert Sound chosen by your daughter is Glass. Settings > Sound & Haptics > Text Tone > Classic > [See the list below].

Here are the iPhone text tones (under Settings → Sounds & Haptics → Text Tone) that have discrete bell-like “ting” sounds with a natural fade:

• Glass – very clear, high-pitched “ting” with a nice decay.
• Note – softer, bell-like pluck with fading.
• Pulse – short separated “ping-ping” with fading resonance.
• Chime – gentle bell chime that rings out distinctly.
• Keys – higher-pitched, discrete ting-ting with quick decay.

Those are the main ones that sound like individual bells rather than continuous tones or synthetic beeps.

Based on your “ting… ting… ting (fading each time)” description, Glass and Chime are the closest suspects.

Settings, sounds and haptics, Text tone, what tone is selected?

then in her contacts for that sender, is there a custom text tone assigned?

if she selects a different text tone and you still get exactly the same weird one then something serious is happening.

Turning the phone off and back on again may fix it.

Check out Sravan's last link

If you have a distorted sound issue on your iPhone --> If you hear no sound or distorted sound from your iPhone, iPad