Justin Bieber and Hailey Baldwin returned from their "road trip" to Disneyland on Thursday after a continuing celebration of the year anniversary of their engagement but all was not well ...

Hailey was sporting a knee brace after the couple's theme park outing. As the couple returned to their Beverly Hills manse, we spotted Hailey's black, stretchy brace, though she didn't appear to be limping.

Meanwhile, Justin's not impaired at all -- he hit the gym yesterday at West Hollywood's newest celebrity hotspot, the DogPound. He took his Lamborghini Urus to go exercise. Hey, he's gonna be one strong dad!