I can see a subtle limp on the second video, at the point, where if there was tenderness in that area I would expect to see this. Very slow gait often picks up "pressure points", this is because more time is on the affected leg/paw and or group of muscles. Equally, when turning at walking pace, this also can be diagnostic of a problem, because it puts unequal pressure on a muscle area, such as the shoulder, or hip.
When Maxx is in a nice flowing trot/run the problem disappears, although to my eye he doesn't extend quite as much on the affected foreleg, that could be nothing though! A good way to check would be to video big circles on lead, first going one way than the other.
A useful exercise is to slow down the video, you can do this to any video on youtube by clicking the settings cogwheel on the bottom right hand side f the clip.
Right now, I wouldn't be doing any retrieves with Maxx, until you have absolutely no doubt that everything is sorted.
PS: More videos please, for no reason other that I love watching Maxx!
