ISBAT delete the content of the second column in the Features Block

### Describe the bug:
ISBAT delete the content of the second column in the Features Block and not have it regenerate the next time I edit the page the Features Block is on.

### To reproduce:
1. Add the Features Block to a page.
2. Delete the content of the second column.
3. Publish the page.
4. View page to confirm it was indeed deleted.
5. Open page in the editor again.
6. See error.

### Expected behavior:
I expected the content of the Features block to respond to editing—that deleting the content of the second column would result in it staying deleted when I re-opened the editor. This is helpful when creating a series of Features blocks and having an odd number of "Features" to add to the blocks.

### Screenshots:
Video of the issue can be viewed here: https://d.pr/v/eATZ1U

### Isolating the problem:

- This bug happens with no other plugins activated
- This bug happens with a default WordPress theme active
- This bug happens **without** the Gutenberg plugin active
- I can reproduce this bug consistently using the steps above

### WordPress version:
5.3.2

### Gutenberg version:
N/A