Caller and receiver audio problems

First of all thanks for any and all relevant input.

So ive had this phone for about two years before giving it to my dad, Two different phone service providers used.

The problem i am having with the phone is that occasionally, often but not too often, when i call someone we both are unable to hear each other. However if i or they disconnect the call and try again right away we both can now hear each other perfectly fine.

The phone is in perfect condition hardware wise, ive tried some solutions such as disabling google active voice assitant. (so its not constantly using my mic) factory restores multiple times. All volume bars are maxed. No water damage to device.

If you can think of something or need more information plz let me know