Hi Berty. I do not yet have my Mini but I do generally have experience with Bluetooth. Bluetooth devices need to be kept within a certain distance of each other to maintain a stable signal. If the phone is sitting in the cup holder for example, then I see no reason why your music would be distorted unless you were receiving some kind of interference.
Is there any sort of pattern to it, for example are you doing specific things at the time it happens, or are you receiving phone calls that might interrupt the music playing etc.
Is your iPhone an older version with an older Bluetooth version.
Try switching your phone off and on again in the event it's a software issue that might benefit from a soft reboot.
I just posted a thread about the same issue... Didn´t see your thread until now.
I´m having the same problem... it fastforwards, stops then it resumes. I have done several things and still the same issue (unpair, pair againg. restart my phone, download different songs). Hopefully someone can help us both.
What I havent tried is turn off mobile data on my phone... Maybe all msgs from whatssap breaks the signal or something
What I would do to troubleshoot the issue is to connect your phone via USB, if that works properly then at least you can eliminate it being a phone problem (or a particular app, such as Whatsapp), as I believe the behaviour would be the same whatever method used to transfer music. If it is the same, then that would eliminate it being a Bluetooth issue specifically and more a phone or app issue.
Actually I tried what you say and it works perfect. So I know it´s not the phone, maybe something withe the bluetooth... Making and Answering calls via bluetooth no problem at all...
Funny thing, after posting about the issue all yesterday I used the bluetooth audio and no problems hehe