Please accept my sincere apologies both for the issue you’re experiencing, and for the delay getting back to you!
Interestingly, I’ve just had an identical report of this issue from a different customer with a Nazgul after they (themselves) updated to BF4.5. I’m wondering if there’s an issue with compatibility with these specific setups on that new firmware. It seems to affect some models and not others.
I was unaware of this, however, I have found advice that there was a change in BF4.5 regarding the correct “port” setting for the O3 unit.
On UART1 in the Ports tab, under the “Peripherals” column, there’s supposedly a new option: “VTX (MSP + Displayport)”, which needs to be selected for the O3 unit to behave. If you select this option and save, does that lead to any improvement in the behaviour?