Spam and Blackberry

I have a drone setup on an old Mac laptop running NoSleep that I use as a media server and to clean up spam from my various email addresses. I access my emails from a variety of devices, including a couple of laptops, an iPad,an iPhone and a Blackberry Q10. When I train an email as spam on the drone it immediately disappears from the mailboxes of all other devices except the Blackberry. Why?
The Blackberry email account is setup to access the same IMAP account on the email server that the Mac/iOS devices access do. Does anyone have any idea why the behaviour is different?
Thanks

There are different levels of IMAP support. It may be that the Blackberry is using an older polling method where it has to periodically scan all the mailboxes to see if anything has changed. Newer clients have a way of being notified, almost instantly, when there was a change.