An issue has been identified in the Mist UI affecting specific WAN templates where incorrect archive configuration is allowed during setup. This leads to a UI rendering failure when attempting to access the affected template. The problem stems from improper validation in the UI rather than any backend or API malfunction.

Mist engineering has confirmed this as a UI bug and a fix is planned for a future release.

When accessing a WAN template (e.g., "StarlinkV5-Hecla"), the following error appears:

“An unexpected error occurred - please reload the page”

The gateway template has remote_syslog.archive = {"files": 10} without the "size" field

Per Junos documentation, archive requires both size and files to be valid

Mist engineering will address this issue in an upcoming release (target: July 2026).

Please contact JTAC for workaround if issue is encountered.