Timestamp not showing up in template node when using moustache syntax

I'm using simpletime to try to inject a datestamp into a flow. I use a change node to set msg.timestamp, and this seems to appear in the debug node as a string. Great.

However, when I use a template node in an attempt to set a http response, the {{msg.timestamp}} will not show up, even though setting a debug node after this still shows that the timestamp is available as a string.

Unfortunately I can't share the whole workflow - so I hope this give an indication of whats happening. Relevant section of the flow, and a screenshot of the debug output.

Screenshot

image

Try {{timestamp}}