Email sent multiple times

(this was with 1.4.2, I just upgraded to 1.4.3)

Hello,

This morning, a programmed newsletter was sent (created a few days ago but set to be sent this morning).

Some one our users received the newsletter 9 times, some other 2 or 3.
I checked the wp_knewsubmits and wp_knewsubmitsdetails in the database and I can only find one entry per user for this newsletter. There isn’t another newsletter with the same infos or which has been sent this morning.

But if I check our mail server logs, I can see the multiple expeditions.

The mail server or modified hasn’t been upgraded recently and we don’t have this kind of issue with others scripts or emails other than knews.

Any idea ?

Thanks.

https://www.ads-software.com/extend/plugins/knews/