TJS ChatMessage doesn't include the standard chat header

I'm having a weird problem (as usual for me) where in this paraticular system, chat messages that use a Svelte template are being generated without the standard header (i.e. time ago and trash can for deletion).

I had it working fine in another system, ported it over to this system and now it's excluding the headers and I can't for the life of me figure out why. Any clues?