Can’t edit post after adding TOC

Plugin appeared to work great, TOC functioned just as I needed, however when I got back and try to edit the post where I added the TOC it loads up blank.

Inspector is showing me the following error:

Uncaught (in promise) SyntaxError: Unexpected token u in JSON at position 2
    at JSON.parse (<anonymous>)
    at save (index.js?2ea8:103)
    at Rt (blocks.min.js?ver=423068d7079f57cf9f02458ccb4a6131:3)
    at Ft (blocks.min.js?ver=423068d7079f57cf9f02458ccb4a6131:3)
    at block-editor.min.js?ver=704b9a6d689b18b6982a8b2ae902e7ec:50
    at hooks.min.js?ver=552e55b6e60db2edbd9073097f2686f7:2
    at Dr (blocks.min.js?ver=423068d7079f57cf9f02458ccb4a6131:3)
    at Hr (blocks.min.js?ver=423068d7079f57cf9f02458ccb4a6131:3)
    at blocks.min.js?ver=423068d7079f57cf9f02458ccb4a6131:3
    at Array.reduce (<anonymous>)

If I deactivate the plugin and I can edit the post once again (and the TOC is turned into an HTML block).

Any ideas? Thank you in advance!