Steps to reproduce:

1. Create a new post and add a table block with some text in each cell.
2. Click the "Align center" option in the toolbar to center all of the text.
3. Publish the post and view it on the front end.
4. Edit the post and choose the "Align right" option.
5. Update the post and view it on the front end.

Result: centering makes the table appear full width and all text centered in the editor but neither is centered when the table is viewed on the front-end. Right aligning the table make the table move to the right but the text is not affected and neither the table nor the text is right-aligned on the front end.

h/t Radu Constantin for the report at https://make.wordpress.org/test/2018/09/05/call-for-testing-gutenberg-3-8-pre-release/#comment-1042

^{Seen at https://madefortesting.com/wp-admin/post.php?post=507&action=edit and https://madefortesting.com/2018/09/11/table/ running WordPress 4.9.8 and Gutenberg 3.8.0-rc.1 with the Twenty Seventeen theme active and using Firefox 62.0 on macOS 10.13.6.}