Odd cause Jasper (the walker hound I was training at the shelter) pulled like he was playing tug of war, & it stayed on.... one thing I noticed that was wrong with the pic u showed.

Look at the strap that is loose at the front of his throat. Max's is snug.. was urs loose?? maybe that was a factor?
cause that Pic is the one off the box I got Max's Halti...
I'm just bewildered that urs came off & I've trained so many dogs on it & not once did it come off.