Plugin's @channel mention's notification not work

Mention to @channel using plugin in mattermost does not work with notifications

Steps to reproduce
Use Docker image is “mattermost/mattermost-enterprise-edition 7.1”
example this plugin used GitHub - scottleedavis/mattermost-plugin-remind: a mattermost plugin that sets reminders for users and channels.
post to this message

/remind ~town-square in 1 minutes "@channel massage"

But this message is not notifications just shows up as unread, but displayed in the Recent Mentions.
Of course @.chnnel from other users and @.user from plugin works fine for notifications.

Expected behavior
I would like to be notified of mentions.

Observed behavior