After updating Gutenberg to 7.9.1 from pre 7.9 I noticed that code blocks in the Gutenberg editor were:

1. Rendering strangely
2. Un-selectable
3. Randomly receiving keystrokes

Below is a screenshot with Gutenberg 7.9.1 without this plugin activated:

Note that the toolbar shows that the code block is selected and the block itself is rendering as expected.

Now with this plugin activated:

Note:

1. The toolbar no longer indicates whether the code block is selected or not
2. The block itself renders full page width, none of the other blocks do that
3. The code block sometimes receives keystrokes but for the most part is no longer editable

Downgrading Gutenberg to 7.8.x resolves the problem.