There won't be any problems for BLE connections due to unshield.
Have you set the ECO capacitor trim value in the firmware for the module? If not, please try setting it. The unreliable connection may be because of that. Please refer the following KBA:
For setting ECO capacitance trim value in firmware for CYBLE-012012-10, add the following code in the CYBLE_EVT_STACK_ON event:
CY_SET_XTND_REG32((void CYFAR *)(CYREG_BLE_BLERD_BB_XO_CAPTRIM), 0x0000BCBC );
Thanks & Regards,
OMG, this turns out to be a key factor in the reliability of the communication between the Android phone and the CyBLE module which has been driving me nuts for the last couple weeks. That ECO capacitor trimvalue line made an immediate difference.
On an iPhone6, I had no problems at all. But with the Android Nexus 6P, the connection was completely flaky and the BT stack seemed to just go nuts on the phone (likely due to data corruption). I think this needs to be better communicated in existing appnotes and demo videos, as you would otherwise lead people down a path of doing what they think should be working, but does not.
Still, thank you for this bit of information. I have more work to do, but (at first glance), it seemed to have solved a huge problem of my project not working!