Yes, the subject line is correct. It is stranger than that, too.
I am using 8.5.2 [8795]
I have a Notebook with many Sections.
The Notebooks pane is open, with the many sections displayed.
Most section names end with a year.
When I selection a section, then use the right-click menu and select "move," then choose where I want to move it to and then <ENTER>, the Section is moved, but the year is incremented by 1. So, 2025 becomes 2026.
If there is NOT a year, or any number, at the end of the section name, a space and the number 2 is inserted.\
Drag and drop does not do this.
How's that for weird!
[confirmed] Righ-Click Move of a Section Increases the number at the end of a Section Name
FWIW: I can reproduce the issue
That's a weird one, indeed! I will fix it in the next update.