Writing Flow: Error merging paragraph block following linked paragraph block

[aduth]

Describe the bug

(Note: Details are rough as I report this merely with the reliable steps to reproduce, debugging will surface additional insights)

To Reproduce

1. Navigate to Posts > Add New
2. Click into the "Write your story" prompt
3. Add some text
4. Apply a link to the text
5. Ensure that the caret is within the inline boundary
6. Press Enter twice
7. Press Backspace
8. Observe error

Desktop:

OS: macOS High Sierra 10.13.6 (17G65)
Browser: Google Chrome Version 67.0.3396.99 (Official Build) (64-bit

Additional context

Error text:

TypeError: Failed to execute 'selectNodeContents' on 'Range': parameter 1 is not of type 'Node'.
    at placeCaretAtHorizontalEdge (http://editor.test/wp-content/plugins/gutenberg/build/dom/index.js?ver=1533663256:2355:9)
    at BlockListBlock.focusTabbable (http://editor.test/wp-content/plugins/gutenberg/build/editor/index.js?ver=1533663256:12954:91)
    at BlockListBlock.componentDidUpdate (http://editor.test/wp-content/plugins/gutenberg/build/editor/index.js?ver=1533663256:12899:14)
    at commitLifeCycles (http://editor.test/wp-content/plugins/gutenberg/vendor/react-dom.24169eaf.js:14947:22)
    at commitAllLifeCycles (http://editor.test/wp-content/plugins/gutenberg/vendor/react-dom.24169eaf.js:16040:7)
    at HTMLUnknownElement.callCallback (http://editor.test/wp-content/plugins/gutenberg/vendor/react-dom.24169eaf.js:140:14)
    at Object.invokeGuardedCallbackDev (http://editor.test/wp-content/plugins/gutenberg/vendor/react-dom.24169eaf.js:178:16)
    at invokeGuardedCallback (http://editor.test/wp-content/plugins/gutenberg/vendor/react-dom.24169eaf.js:227:29)
    at commitRoot (http://editor.test/wp-content/plugins/gutenberg/vendor/react-dom.24169eaf.js:16181:7)
    at completeRoot (http://editor.test/wp-content/plugins/gutenberg/vendor/react-dom.24169eaf.js:17196:34)