First of all, what is latency?
It's the delay between an audio signal being sent and when you can hear it. You won't hear it when you're listening to music, but you might notice it while watching videos or playing games, as the sound is out of sync with the picture.
The same thing happens in BandLab - you might notice your recording being out of sync with the metronome or the previously recorded track.
Is there a way to fix it?
No, sorry about that! Bluetooth connection has a natural unfixable latency, so we do not recommend using Bluetooth devices for recording.
Latency can vary depending on the hardware of your phone and the Bluetooth device you have. You can reduce the latency by making sure the Bluetooth device is fully charged and held close to your phone, but there's nothing you can do to get rid of it for good.