Steps to reproduce:
Result: text in some or all of the table cells does not get saved. (30s)

Seen at http://alittletestblog.com/wp-admin/post.php?post=15433&action=edit running WordPress 4.9.8 and Gutenberg 4.2.0-rc.1 using Firefox 63.0 on macOS 10.13.6.
/hat tip Mario Neuhold for the original bug report at https://wordpress.slack.com/archives/C02QB2JS7/p1541020677377700
I think #11287 should fix this. I did a quick test and table seems to work fine with that PR.
closed by #11287
Most helpful comment
I think #11287 should fix this. I did a quick test and table seems to work fine with that PR.