Lightbox setting gets disabled with each post edit

There is an issue with the Co Block plugin. If images in a post have the lightbox enabled, and you then go to edit the post, the lightbox is disabled and has to be activated again.

Co Blocks version 3.1.15 and 3.1.16

Steps to replicate:

1. Activate the CoBlock plugin on a site.
2. Create a page or post and add an image.
3. Select the lightbox option in the block settings to make the image.
4. Save the page or post.
5. Exit the post and click edit again.
6. Make a small change and save the post again.
7. Check the image that had lightbox and see option is disabled.

Kasia