I've been noticing somenthing like this. The behavior is basically what Mark explained but the LED on my OWL sometimes goes off and sometimes stays red. The key is that only happen when I power up the power supply with the OWL connected. If I disconnect the DC jack and connect it back it works.
I read somewhere in the datasheet of the STM that it is recommended to put a 100n cap across the NRST pin and ground because if the power supply raises slowly it can trigger a reset and the thing won't boot up.
I wanted to try this but I guess I never had time.
Maybe this is the problem.
@markdibarry: could you try powering up your power supply with the pedal connected and see if the problem is regular (to me half the times I do this doesn't work) and with the power supply on disconnecting and connecting the DC jack? That would confirm that we have the same issue.