By default, the number of allowed characters in a single cell (except column A) is 1024. This limitation is intentional to optimize the loading speed of the dynamic content for users who don’t need a higher number of characters.
To change the max allowed number of characters in the relevant column:
function modify_content_column(){
global $wpdb;
$wpdb->query("ALTER TABLE {$wpdb->prefix}ifso_bulks_content MODIFY COLUMN content VARCHAR(2048);");
}
add_action('init','modify_content_column');
The code above will change the number of allowed characters to 2,048. You can replace the number in the code with any other number. Bear in mind that if your file consists of many dynamic versions (thousands), there might be some loading speed implications (they will probably be insignificant, but it is worth checking).
Please note that if you reduce the number of allowed characters, the new number you set will affect content created in the past.