Just so I understand correctly. The main issue you’re facing with Cash App, appears to be the handling of Lightning Network invoices that are for zero satoshis (sats) as Cash App generates invoices without specifying an amount, which means the user must input the desired amount manually and many Lightning wallets do not support this functionality, which requires an amount to be specified in the invoice prior to sending to process the payment which creates difficulties in completing transactions with Cash App invoices. 

Does that sum it up accurately?