Two questions about Focus 40 5th generation: Existing connection and display freeze

Dear fellow AppleVisers,

I'm dropping these questions here since my local FS support hasn't managed to come up with an answer, or a solution.

Firstly, in the Connections menu of the Focus 40 )and 14, I've seen), there is already a connection in the list. Its name is VFO-1-PC (not counting the BT1 pointing to it being connected to channel 1). Does anybody know what it is? Do you need it for anything? I've googled myself silly but haven't found anything. The FS technician that took a look at my display to try to figure out why I have so much problems with using it with my phone (see below) deleted it from the list, because he thought it was the "root of all evil", but it doesn't seem to have improved anything. He didn't know what it was or what it's used for.
Does anybody know what it's good for, if it's good for anything? What does it do? Why is it standard in the list on these displays?

Secondly, I've had this display since January, after the first one I got got replaced due to technical issues. However, this Focus 40 also behaves weirdly with my phone (iphone SE, iOS12.1.4). In the middle of typing, scrolling, working, it suddenly freezes without warning and only starts communicating with the phone again if I turn it off and then on again. If I'm lucky, that is. Sometimes I have to turn it off and on a couple of times before it wakes up, sometimes also turn VO off and on again. VoiceOver still sees it as active and VO doesn't crash itself, only the display. I have similar problems while using it via Bluetooth with my PC running JAWS 2019. Unfortunately (for me AND the technical support), there is no pattern to the behaviour - it happens spontaniously, sometimes twice in 15 minutes, sometimes hours pass without anything weird happening. It also happens in different situations and apps, not always in the same spot or after executing certain commands. I can't reproduce it for a technician to take a look, it just...happens.

So since it didn't do its job, I sent it for a checkup. I got it back from reparation yesterday, but the FS support here hadn't figured out what the problem was. The display behaved itself while they had it, it never even once froze or refused to communicate. They replaced the main board, just in case. I used it for 4 hours yesterday, then it crashfreezed again, refusing to respond to the phone. I also connected it to my computer, just to test, and after an hour or so, the same happened there. (I never have any of these problems while using the display via the USB connection to the computer, only when it's running on Bluetooth.)

Do these problems sound familiar to anyone here? Does anyone know what causes them and what might be the solution? It's driving me nuts and it's not really very motivating to go to the technical support again when they don't seem to know what's going on, how to reproduce the problem or how to solve it. They claimed to have worked with it for 1.5 day without problem, and I get troubles after only a couple of hours.

What's confusing me endlessly is that we also have a Focus 14 here at home, and I have none(!) of the problems the 40 causes me with the 14. Not. Ever. Not even once. So, if it was something wacky with my phone or computer, one would think that the Focus 14 would react the same way. But nope. It ticks on like a happy clock. I've also paired the 40 to 2 different phones and 2 different computers without seeing any difference - same troubles come up after a while, no matter which device it's connected to. And, the 40 I had that got replaced had similar issues to this one.

Device specs:
Focus 5 40, firmware version 5.81-40. (Same goes for the 14)
iPhone SE, iOS12.1.2.
DELL laptop running Windows 10 v1809 64bits, JAWS 2019.1903.47.

Many many Thanks in advance for any answers, ideas or tips.

Best regards,
Shass