Samsung Galaxy S3 (SCH-R530C) and Square-up Reader, Makes problem for bluetooth?

[TheLandYacht]

I use bluetooth for all my phone calls, and up until recently...when I made the switch from an HTC phone to the GS3...simply left the Square-up reader plugged into the 3.5mm jack all the time (I tend to leave the phone hanging on the dashboard & don't touch it).

I've found that I can't do that with the GS3, as when the card reader is plugged into the 3.5mm jack, it disables (greys out as an option in the "phone" app) Bluetooth.

Is this just my phone? Can someone else with this model test to see if yours does the same?
Is there a setting somewhere that I can change to fix this? Some other workaround that'll allow me to keep the Square plugged in & continue using BT?

Help is greatly appreciated.

BTW, if it matters:

SCH-R530C on Cricket
Android 4.0.4

Edited: Title, to clarify a bit.

 

[meyerweb#CB]

I suspect not many here are using the card reader here, so we probably can't offer much help. Have you tried asking Square Up? They may have some experience with their device and the S3.