Hmmm. It sounds like you've covered your bases.. I'd either do a factory data reset.. Which they will want you to try before swapping out the device..or call customer service or go into your local store.. See what they say..
You're not using any apps that may be causing this? Ringtone makers or anything?? I had one that caused this on my Maxx.. But that was a while ago
I should add..my turbo acted up when I first got it too.. The dialer wouldn't come on the screen when I'd open the app.. I had close it and reopen.. I didn't have my animations turned off.. So there was no reason for it.. It would also. Switch to speakerphone in the middle of calls... A factory reset cured these issues..
I found the problem and yes, it was my fault. I have an audio level app (audio manager pro) and when I reloaded the app after getting my new turbo I added shortcuts to my different profiles on my desktop.
The problem is when the app was downloaded all the ringtones and notification sounds got reset to default settings of the phone. I didn't notice that so when I created my shortcuts they also were saved with the default sounds. Even though I changed the sounds in the main app I never saved it to a profile so when the app refreshed it reverted back to default.
I went back into each profile, changed the sounds and saved. Now it all works.