I have a CQ-18T and have discovered that the built in Bluetooth is unreliable for iPhone audio playback (audio stops/gaps/&speeding playback) IF you also have 2.4Ghz WiFi enabled. Switching the built in WiFi to 5Ghz fixes the issue. Others have also noticed this problem.
Interestingly however – my iPad (gen7) would bluetooth audio connect OK to the CQ-18T with 2.4Ghz Wifi enabled! Perhaps this is an iPhone to CQ Bluetooth only issue??