I'm experiencing the same issue.
They are not battery or other notifications, the headset seems to restart and goes through the power-on voice prompts all over again. During that time, the headset appear as disconnected from the PC, forcing some communication apps to switch to another audio
device, or even crash (Skype doesn't seem to handle the sudden device disappearance well).
It is not a disconnection initiated by a problem from the PC side, as even if the Bluetooth stack crashed, or is manually disabled through device manager, the headset would then play the "You're disconnected from [PC name]." and only the "You're connected to
[PC name]." when Bluetooth is available again.
Instead, what we're experiencing is the headset stops audio completely, plays the full power-on "Hi, you've got about [time] hours of battery left. You're connected to [PC name].", and temporarily appear as disconnected from the PC.
This makes the headphones very inconvenient to use for music, and simply impossible to use for conference calls, at it can just stop audio for several seconds at any time.
Already tried resetting headphones to default factory settings through the app, as well as pairing only the PC (not the smartphones). Still happens shortly after reset and when paired to a single device, and pairing only for audio, cancelling the new Office
Bluetooth LE secondary connection when requested.
This happens several times a day, regardless of the remaining battery capacity.
Surface Headphones 1st Gen
Firmware version: 1.0.4.44.21
Hardware version: 1830-120
Language: English (US)
Connected to Surface Book 2 15"