Good morning,
I have got same error ("Error decoding JSON data: Control character error, possibly incorrectly encoded").
When checking the JSON settings using the json-db-check.php i get the error:
Row 10088 is not valid JSON. Error: (Control character error, possibly incorrectly encoded)
Content: {"bootstrap4":"-","loadfonts":"{\"PlayfairDisplay\":{\"name\":\"PlayfairDisplay\",\"weight\":[\"400\",\"400i\",\"700\",\"700i\"]},\"Quicksand\":{\"name\":\"Quicksand\",\"weight\":[\"400\",\"500\",\"600\",\"700\"]},\"JosefinSans\":{\"name\":\"JosefinSans\",\"weight\":[\"300\",\"400\",\"400i\",\"600\"]},\"IbarraRealNova\":{\"name\":\"IbarraRealNova\",\"weight\":[\"400\",\"400i\",\"600\",\"700\"]} }","loadconfigicons":"{\"awesome_icons\":{\"awesome_icons\":true,\"url_type\":\"cdn\",\"custom_url\":\"null\"},\"material_icons\":{\"material_icons\":true,\"url_type\":\"cdn\",\"custom_url\":\"\"}}","btAssigned":""}
This row in the database has been put there after installing the ja-pagebuilder-component_1.0.0_alpha5.zip
Hope you can adjust it at the next released version.