I had the same problem. Click at the end of the line and the cursor would appear 2, 4, or many more characters before the end of the line. However, then I would start typing, and the newly typed characters would appear correctly at the end of the line. So it was just the blinking cursor appearing at a different place than where it was actually ‘behaving’.
I’m working with Obsidian 0.9.6 on Windows 7.
After reading ryanjamurphy’s reply, I turned off the Custom CSS plugin, and the problem went away. I turned the plugin back on, thinking I would alter my customized CSS file until I found the portion of the file responsible for the weird cursor behavior, but the problem did not return. So I’m using the same custom CSS file as before, but the problem is thankfully gone. I also restarted Obsidian to see if the weird behavior would come back, but it didn’t.