The problem is it says “Invalid timestamp”. It has the correct timestamp in it and I can display the timestamp in lovelace, but for some reason it doesn’t recognize it as a timestamp and therefore doesn’t interpret it correctly in lovelace.
Try adding “as_local” to your template. For me the attributes “last_changed” and “last_updated” return a datetime object set for GMT… maybe that is conflicting with something…?
Blockquote Try adding “as_timestamp” to your template. Though, the docs say device_class: timestamp should work with datetime objects like “last_changed”.
Ha! I almost mentioned that as it is what I use for a more compact “glance” type display. Thought I’d stick with recommending core cards as the custom button card can be a bit daunting with its number of options.