"respect of validated end date" alert generation after activities import

Hello,

I have imported a list activities by the import tool.
After importing, I get a warning and an alert for activities whose status is "done" (their "done date" is in the past).
The generated warning/alert refer to the indicator "respect of validated end date".
Please note that the "done" activities have actually a "validated end date" in the past.
However, since these activities are already completed, I would prefer to not receive any alert for them.
How can I avoid the generation of alerts when importing activities already "done"?

Regards