Hello, this concerns SoftDevice spec 7.1 and nRF5 SDK v16.0.0.
I noticed that ESB has interrupt handlers occupying priority levels 0 and 1 according to the SDK documentation. However, the SoftDevice uses priority levels 0, 1, and 4, and the documentation states that the application programmer must refrain from using these.
So just to verify, I assume that Nordic has implemented ESB in the SDK such that it "plays nice" with an enabled/active SoftDevice (e.g. using radio timeslot API)? Because it seems that at least the ESB timer interrupt may interfere with SoftDevice activity.