This fixes the icon, thanks - but still doesn’t seem to allow me to pin to the launcher (Ubuntu 26.04, default GNOME desktop).
I can confirm this: I also saw this problem after updating to the latest version of Obsidian, and copying the launcher to ~/.local/share/applications/obsidian_obsidian.desktop fixed it for me. The key indeed seems to be the file name. The only downside of copying is that I now see two identically looking entries for Obsidian in the app search (after pressing the Windows/Start key), and only one behaves correctly.
Do we know if they will push this update?
I have received an update that fixed the image in the dock - still waiting on one that fixes the spell check