linking Add secondary_info: last-triggered for entities-card which has been implemented, and this issue https://github.com/home-assistant/core/issues/32179 concluding and reporting the fact script dont have a surviving last_triggered.
As Phil suggests, this might not be an issue (since they never had), and though I would think that a design oversight, because they really should, I issue this FR, to do so after all.
Please consider making the script attributes last_triggered survive and restore after a restart, so we can use that in our logic in the front end backend of modern day Lovelace/HA.