This happens to me in the Linux desktop Appimage: V1.0.179 as well as 1.0.193
Encryption is enabled (quite a while ago) and worked so far on the Linux desktop Appimage and on two Android devices.
Now one note (which was edited a few days ago on one of the Android devices) in the Linux desktop Appimage shows up as Encrypted (and a key symbol) in the list of notes. No content of this note is displayed. It is still listed in the mobile app (and can be edited there).
Encryption setup still looks good on all devices.
Any help/suggestion how to decrypt this note?