Hi,
thanks for your post, and sorry for the trouble.
The reason for this is that some other plugin is interfering with the save process of tables here.
As you have found, the n is a result of a line break in a cell. The reason for this is that line breaks are internally treated by the string “\n”. Now, some plugin is interfering and most likely running the stripslashes()
PHP functions on all data that is sent to the server by the browser. This then removes the “\” from those line breaks, so that only the “n” remains.
So, to fix this, you will need to find the plugin that interferes here, and then that plugin needs to be fixed.
To do that, please try deactivating all plugins except TablePress and re-activate them one by one, and check each time if the problem reappears. WIth this, you can find the plugin that causes this.
Regards,
Tobias