Like all weight loss, you will lose lean muscle mass and bone density as part of it if you do not take corrective measures. And even with such measures, you will likely lose some either way for the medium term. It's very difficult to lose only fat during a long term calorie deficit.
The answer is getting into a regular schedule with resistance weight training. Obviously not all that many people will pull it off, but if you can pull it off you can stave off the worst of the side effects in many cases.
From what I've seen it's mostly related to just losing weight in general (less weight -> less musculoskeletal stress -> weaker bones and muscles). Weightlifting can counteract it.
I have a composition scale, and regularly get vitamin d, and calcium tests (had issues with both) since taking the wegovy pill in Feb, I have not loss any bone density, and pretty minimal amount of lean muscle (i think any weight loss will have some lean mass loss). I have lost fat, kicked drinking, and my lipids improved dramatically.
Asian ai startups have also no way to compare despite making bold claims, and one could argue the whole point of the trump intervention was to prohibit them from distilling faible.
