I've reopened a project to work on. Every time I select shape I've drawn and filled it just changes into a circle. It's making this program unworkable at the moment. Lines also change when clicked on and undo is not an option to fix it 

1. Describe your OS (your computer's Operating System: Mac/Windows/Linux/etc. & version).
2. Describe if Inkscape was newly installed, or upgraded from an earlier version.
3. Describe the version of Inkscape and the installer you used (the file you downloaded from the website: .msi/.exe/.zip/other ). 
4. Describe any special hardware being used, like tablet/stylus, external drives or multiple monitors.
5. Describe any helper/assistive programs or keyboard modifiers (macros, languages, etc.).

Bonus points, if you:

• Attach* a screenshot of the issue.
• Attach* an example SVG file that has the issue.

On a Mac, installed two days ago from a dmg file. Post edited with screenshots and file 

The artwork contains many scribbly paths that are likely causing a number of issues.

I'd try composing simple shapes with basic pen and pencil tools, using node editing to refine the shapes.

The misbehaving paths have two active path effects, [Simplify] and [Spiro Spline]. Selecting all [ctrl+a] and [Path > Remove Path Effect] seems to restore the expected result. I'm not sure why the distortion only occurs when you select the affected paths.