If your post includes Unicode, make sure you choose one of the last two options in the pull-down menu:

using UBBCode
using HTML
using HTML and UBBCode

In other words UBBCode does not support Unicode.

(Here are the Unicode characters that you included in your post: Я ‽)

While this was not a bug, there were some other bugs in the software update and the developer has released a bugfix that I'll apply over this weekend.