Not entirely true. Q30 you can connect to two devices concurrently but if you connect to a newer bluetooth version first it cannot then connect to an older bluetooth version 2nd.
What can happen is the phone gets connected first, then won’t connect to laptop as most phones are bluetooth 5 and most laptops bluetooth 4.2.
Even if you do connect correctly to oldest first, say connect laptop then connect phone, as bluetooth has hiccups, disconnects, they can then try to connect in the reverse and so break. When that happens you experience either a crackle or a disconnect.
Best is to dedicate headphones to the laptop exclusively, never pair it with anything else like a phone to make it the most reliable. If you do want to swap between then disable the bluetooth of the other device you don’t want connecting accidentally.
As what I’ve written above is relatively complex, most people don’t understand the topic, the simplest reply is “reset the headphones” as that deletes the pairings so then when they try to use first what didn’t work, then it works, but then they go and pair it again with another device, the problem returns, the fault is not Soundcore’s but they get blames as “brand XXX works fine, returning Soundcore” when in reality the other device was an older bluetooth version and so the problem never happens. It’s not Soundcore’s fault.
Bluetooth is backwards compatible, not forwards compatible, so if you have different versions of bluetooth you have to connect to oldest version first. Most people don’t know what version they have.