I'm not there to see it, but I know during molt my Runners can appear to have Angel wing for a day, then it corrects itself. The feathers seem to twist in their sockets.
I have had that happen where I can tuck the tip back under and it stays. I decided to just go ahead and tape these two to make sure the tips go back under the wing since the drake's wing seemed more twisted and it has been for a week or more now. Sometimes I see a wing stick out briefly and then the duck is able to tuck it back under on its own but it concerns me if it is a genetic weakness that needs to be removed from the gene pool. I think the hen would have been fine without taping but it does not hurt so we went ahead and did her wing when we did his and I am considering selling them at a discount as pet quality instead of keeping them to breed just in case it is at all genetic.
I sometimes wonder if they get their wing twisted the way we would twist an ankle but the extra weight of the blood in the feathers keeps them from being able to get the tip twisted back under where it belongs in order to heal the strain or sprain. I have only seen it happen while the blood feathers are weighing down the wing tip but we have hardly had it show up in our flock and when it does we sell them as pet quality instead of breeding quality.