About the post you linked, see [1] and [2], which makes me question both whether that is an actual vulnerability (Signal, the messenger recommended by the author, also didn't have that check, and it's addition is absent from release notes and CVEs) and whether the post was made in good faith (the check was added to libsignal on the same day that the author disclosed the vulnerability to Matrix, which can be a coincidence, but doesn't seem likely given that the code has been there for years).

Can't speak about the other issues, I haven't had those but I barely use it. Based on comments, it's clear they exist or have existed for quite some time.

[1] https://blog.erinshepherd.net/2026/02/non-contributory-keys-...

[2] https://matrix.org/blog/2026/02/analysis-of-reported-issues-...