Dog's Leg Slipping

Two nights ago, I noticed that my dog's rear left leg slips when she gets up from lying on her side. However, once she is standing, she walks and runs without any issues. I've carefully examined her leg from top to bottom and haven't found any signs of pain or limping. For additional context, she is a 10-year-old mixed breed (her mother is a Boxer and her father is likely a Labrador), and we have typical floor tiles in our home. I have scheduled a vet appointment, but it will be a while before she can be seen. In the meantime, I've recorded a video of the issue, which you can view here: https://drive.google.com/drive/folders/1c7B1UJVD25VbWU9vCcXv2lGuD3AjOI4x?usp=drive_link Any help is much appreciated.

Hi - I watched the video and may disagree; subjectively, I think that even before the slips, there may be a fair amount of reduction of weight-bearing on that leg compared with the other.  Lameness can be subtle and to give this a fair test, your vet may want to 'trot your dog up' - i.e. to see them walk in the flesh.  Tiles obviously do not help lameness, and neither do long toe-nails (I can't see to assess them from here, so) these may be things to avoid.  Typical problems that present at first and then are 'warmed out of' include; osteoarthritis, perhaps in connection with hip dysplasia; muscle and tendon problems.  However, there are an array of possibilities and it's great that you have a veterinary appointment booked for a proper assessment.

Thank you so much, for taking the time to watch the video and respond. Are any exercises or home remedies that I could give her in the mean time, until the vet sees her? I have Cosequin Maximum Strength Joint Health Supplement for Dogs at home