20 Republicans had signed on for the lawsuit.Several issues with the proxy voting resolution.
On reuirement of the House Rules, Rule XX is a report must be issued daily by the Sergeant At Arms for the "health emergency" to be envoked. Based on the May 19 letter, no details required by Rule XX 5(c) was provided. If no letter was submitted today, the vote is in violation of the Rules establishing a Quorum by proxy vote.
To give an idea of how severe the health emergency in the House is, most self-isolations were precautionary and the last reported self isolation was April 20. https://www.govtrack.us/covid-19