Formula not calculating

I have used a formula identical to a sample in the CRM app to create a View Detail button:

this is how it is rendered:

"<a style='white-space:nowrap;background:#3A5999;border:1px solid #4165C5;color:#ffffff' href="#View:stmDetail?selected=10000000000048">View Details</a>"

The expression is calculated but the reference is not parsed into a link as I would expect and as it does in the sample app.

Have I missed something or is there a bug running about?

Regards,

Tim Sadler
account: oncalendar
app:oncalendar
shared with support