Hi @Brash,
We're aware of an issue regarding switch summary page on networks bound to templates failing to load. This is being investigated by Engineering. I'll post another comment when it's been resolved.
In the meantime, you can workaround this issue by browsing to on templated network in the same organisation, navigate to the switching > switches > switch page and click on 'show new version', then navigate back to the templated switch(es) you were originally trying to access.