Web UX bug: Domain verification error appears as N messages, one character per message

To reproduce:
1. Verify HTTP or HTTPS (or Replace existing verification)
2. Enter any domain with trailing slash (e.g. shazow.net/)
3. Get something along the lines of:
- T
- h
- a
- t
- _
- d
- o
- e
- s
- ...

Reproduce the issue by using HTTP or HTTPS domain verification with a trailing slash, such as shazow.net/. Trace the web domain-verification error handling and identify why the error text is displayed one character per message; done means the complete error appears as one message.

Written by the indexing model from the issue text.