Can’t edit or add more than one column in the block editor

I think I’m having the same problem as this old thread. After inputting one character, the table only displays one column in the block editor. However, it actually has multiple columns as I see there are multiple <td>‘s. And it renders multiple columns in the preview.

Here is the demo of this problem: https://imgur.com/a/G3Ebyfi

• This topic was modified 5 days, 15 hours ago by chenmantous.