This is 100% true for all of their techs produced within the past ~20 years, but WPF and Winforms are extremely stable with no real issues.
It's so weird too because most of everything they've done in the past 20 years has basically just been incomplete remixes of WPF. If they just stuck with WPF and extended it onward, something like a UI toolkit equivalent of C#, it would 100% be the gold standard for Windows development today, and perhaps even UI development in general if they open source/standarded it.
Stable, but many issues. Stay away if you value your sanity and do anything nontrivial.