I am using selectize (a select2.js alternative). When I am running selectize on my field with 2 optgroups, one of the optgroups disappears \(〇_o)/
This is the HTML of the select field:

This is how it looks in view source:

It seems like the quotation symbol is causing it trouble because if I remove that value from the array before printing the values, the optgroup that disappears now appears. I do need however to have these symbols.
This is the PHP code that generates that HTML:
<select name="output_selected_columns[]" id="output_selected_columns" class="selectize" multiple="multiple">
<optgroup label="<?php echo sprintf( __( 'Columns of %s', 'excellico' ), $file1 ); ?>">
<?php
foreach( $Excellico_Files->get_file_left_header() as $key => $value ) {
?>
<option value="<?php echo esc_html( $value ); ?>"><?php echo esc_html( $value ); ?></option>
<?php
}
?>
</optgroup>
<optgroup label="<?php echo sprintf( __( 'Columns of %s', 'excellico' ), $file2 ); ?>">
<?php
foreach( $Excellico_Files->get_file_right_header() as $key => $value ) {
?>
<option value="<?php echo esc_html( $value ); ?>"><?php echo esc_html( $value ); ?></option>
<?php
}
?>
</optgroup>
</select>
This is how it looks: (missing File 1 optgroup)

I also tried to add diacritics: true to the selectize options object, didn't help.
Any help is appreciated! Thanks!
What should I do?