ringtone changes by itself

Hi bymcdonald,

To help us assist you, can you let us know more about what's happening? To clarify, it seems like this is happening only with some calls, correct? If so, is this happening with calls from certain contacts only? That information will help us plan how to proceed.

If the issue is only happening with calls from certain contacts, let's check if different ringtones are set for those contacts only. This link outlines how to check, and may be helpful: Use tones and ringtones with your iPhone or iPad

Set a ringtone or text tone for a contact

1. Open the Contacts app and tap a person's name.

2. In the upper-right corner of the person's contact card, tap Edit.

3. Tap Ringtone or Text Tone, then choose a new sound.

Thanks!