Could be inconsistencies in the way the invoices are created by the wallet or parsed by the client. I ran into some similar issues with nostr:npub1getal6ykt05fsz5nqu4uld09nfj3y3qxmv8crys4aeut53unfvlqr80nfm and nostr:npub18m76awca3y37hkvuneavuw6pjj4525fw90necxmadrvjg0sdy6qsngq955 recently that had to be fixed with some code changes on the client side because of how the invoices were encoded.