I'm no expert and this is a total guess but I would think at some point the funds will return onchain since only one payment can be made per invoice. Theres a signature handshake and so if that second pmt doesnt receive a confirmation back, it will eventually expire... maybe?

If true, in the wos instance, IDK what happens there since you don't hold the keys... I'm not sure the situation with one key. Would be interesting if you did it again but with a self custody lightning wallet. Maybe in a week those funds return onchain?