Incorrect error message in "Create stream" UI

[nya-elimu]

URL: https://www.drips.network/app/elimu.dao.eth

How to reproduce this UX/UI bug:

1. Type stream name and paste drip list URL: https://www.drips.network/app/drip-lists/41305178594442616889778610143373288091511468151140966646158126636698

The "Stream to" field appears valid (✅).

2. Click another field in the form and edit it, e.g. change the stream name:

The "Stream to" field shows an error even though its value wasn't modified. And now the form cannot be submitted.