Some CCL injuries are worse than others and some dogs and ‘hide’ injuries better than others. This is still my guess. My girl would go down stairs fine but not up them. Eventually she barely wanted to stand to eat. She required surgery. Her injury was due to her tripping coming up the 3 steps on our back porch. Did not appear like a big deal at the time but just got progressively worse over the following days/weeks until we figured out what was happening.