Wrong Code Block Macro formatting

Steps to Reproduce

1. Create a page
2. Add a code block to it with the theme Fade to Grey
   • Preview the page and observe that the code block is a black background with white text
3. Add another code block, and do not set a theme on it
   • Preview again and observe that both code blocks have the default formatting

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Hi,
We've experienced recently some problems with Code Block Macro. Those problems unfortunately started to repeat.

Those are the steps that I've done:
1. Wrote "Logback configuration" section with code block (formatting in attachment).
2. Save the document.
3. Edit and add upper section with another code block (different formatting) + some No Format block (I'm not sure if it's connected, but I think it's worth mention)
4. Save

Now all code blocks (as you can see in attachment) have the same formatting as last code block. I'm also not 100% sure if this formatting is inherited from last code block or just randomly.

I hope it's reproducible and can be fixed easily.

Confluence: 5.1
Code Macro Plugin: 2.0.19

Let me know if you need anythnig else.