Hi @Claud,
Welcome to the eazyBI community!
Thanks for posting your question!
To count the tickets based on a custom date field, please make sure your “Validation date” is imported as a measure. If you import the date field as a measure, you will notice that eazyBI has created a new measure, “Issues with Validation Date” which you can use in your calculations to count tickets based on the custom date and not the issue creation date.
You can also read this community post to see an example - Connecting time measure to Time Dimension - #2 by Elita.Kalane
Best wishes,
Elita from support@eazybi.com