Error decoding JSON data: Control character error

This error is occured when I set Padding and Margin of the middle row (empty row) is between of the first row with images and the third row with images, and then click save.

After save, I could not click this module to modify.
A way I only can do: delete it and rebuild a new one with the same information.

Note: I test Page Builder CK with Joomla 3.8.1 and Exampp

Hi
is it possible that you have a lot of elements in your modules (a lot of content) ?
this is mainly due to a problem in the sql, which truncate the data when too long
you can try to edit hte "params" column of the modules table, and set it as "longtext".
then try again
CEd

Same issue. Twice.
The first time I was working on a really plentiful module, but now it was rather simple: see the attached image.
It sounds strange to me that a so simple module can crash in such a way...

is this a new module that you have created after your first crash ?
The problem is the sql limit that truncate the json string where the params are stored

Try a new module and let me know