Plugin Conflict with Download Manager

I’m wondering if anyone else is having some sudden plugin conflict issues. For me, I presently have two sites (our of seven) that suddenly developed plugin conflicts about the time WordPress 5.4.2 was released. For one site, the conflict is between “Qubely – Advanced Gutenberg Blocks” and “Download Manager,” which is a W3Eden package with homepage at

https://www.wpdownloadmanager.com/

These plugins all worked fine until about one week ago, when they suddenly didn’t work together. I’m happy for any suggestions on dealing with this.

Thanks