Freshchat User API's "last_contacted" date is incorrect

I’m trying to find out the last time a specific user was contacted in any way (phone, IG, WhatsApp), using the Freshchat API

Part of the response when you call GET /users/{user_id} is a last_contacted field, which shows the timestamp of the last time a user was contacted.

I have a user with multiple conversations - some on whatsapp, some outbound calls. For that user, the last_contacted field incorrectly shows the timestamp of the most recent outbound call, even though there have been whatsapp messages in both directions since that time. There have even been brand new WhatsApp conversations created after the timestamp the API reports.

Is this a bug? If not, what is the actual clear definition of this “last_contacted” field?

Is there a straightforward way to identify the last time any form of outbound conversation was sent to a User? My current inelegant workaround would be to retrieve the conversations for that user, then retrieve messages in each conversation, and keep track of the newest one.