Steps to reproduce:

1. start a server (Standart Zabbix server is enough)
2. gather some data
3. Go to Latest Data
4. Find a data with date
5. Hover over an wait for alt text to appear

Result:

Despite Data in the field being converted from unixtime to normalized format
Alt text stays in Unixtime

Expected:
as in other fields data for alt text should be also normalized to human readable date