Ok, there seems to be a few posts on various problems with the DN not playing the first note (Trig on the first step of the new pattern) when Patterns Changes are being controlled externally. It is difficult to discern what answers are being suggested for which situation. In my case, I am using an OT MKII to send pattern changes and the DN is set to follow. It is real bummer. Is this a known issue?
Also; it appears to be intermittent.
A year later and the problem still persists.
Wonder if there’ll ever be an update fixing this bug.
The workarounds are limiting and often require altering the entire chain sequence by altering the midi values, In order to to make sense.
This particular issue makes it by far the worst slave Instrument I’ve ever come across.
External pain!
Other than that it’s great! 
I’ve had this problem too. I’ve not read much about it but I find shifting the micro timing a little late sometimes helps.