Multiple file upload limited to 20 photos

I am using UPG Pro with a shortcode form allowing multiple file uploads. When uploading more than 20 photos, the upload appears to complete successfully with no warnings or error messages. However only the first 20 photos are added to the media library and as posts in UPG. This is the shortcode I’m using:

[upg-form-tag type=”file_multiple” title=”Click or Drag & Drop to upload multiple photos” class=”upg_drag_file” multiple=”true”]

I’ve tried changing the advanced setting under the “Bulk Upload” tab, but it doesn’t seem to have any effect. Is there a way to allow more than 20 photos to upload at once?

I’ve tried using the bulk upload layout instead of a custom shortcode form, and that works correctly. But I prefer the look of the standard multiple file upload.

Thanks!