Jira Automation

Hi All.
I am using Jira automation rules.
On every event (Ticket creation, Ticket transition, Ticket deletion, User Assignment…) Jira sends me web-request with the standard Jira object for the given Ticket. That object containd information about all the users included (Assigned user, Ticket creator…). This information contains users email addresses.
Only in case of an event when some user puts comment on the ticket, I am receiving the same standard Jira object for the given Ticket, but without users email addresses.

Is there a bug in Jira automation service?
I am getting the users ID’s, is there a way to call different Jira API sending the user id and receiving the user email address?
Any advice?