Any way to use scissors to cut shapes more reliably?

Hi everyone,

I'm using shapes to make some elements of my drawing scalable.  I'd like to cut certain parts of shapes and use the scissors tool.

However, the tool is frustrating in that it doesn't reliably register a "cut" even when I place the tool visibly directly on the line.  What am I missing?  Are there any tips to make this more reliable?

Running Painter 2022 & Windows 11 on Surface Book 3.

Thanks in advance.