A cloud site in Standard/Premium evaluation has the same email notifications limit as Free plan.

Ref: Limitations in Jira Cloud Free plans, Email notifications

Jira can send a maximum of 100 emails per day on the Free plan
 

 When a cloud site reaches the limit, the message is shown like this.

You've sent the maximum number of notifications in 12 hours for your plan. <link to plan page> Upgrade to keep collaborating with your team.

This message is very confusing for users who are already on Standard/Premium evaluation because they have nothing to do except expediting the end of their evaluations. 
 
Please modify this message like this:
"This limitation will be removed when you move to Standard/Premium (paid) plan after your evaluation period." 

Also, it's nice that Atlassian prepares the documentation explaining the limitation during the evaluation period.