Y_ASUSI have ZB601KL and I am using the OnePlus bullets wireless Z, I think you didn't read properly what I said.
Is your phone ZB601KL or ZB630KL?
Please also tell us your firmware version: Settings > About phone > Build number.
Please try resetting your network settings and try again. (Settings > System > Advanced > Reset options > Reset Wi-Fi, mobile & Bluetooth)
Could you describe the bluetooth problem in more details?
What app/app version are you using? What are the steps to produce the problem?
Does it appear on different Bluetooth brand/models? What's the brand/model of your Bluetooth?
Thank you 🙂