Chrome OS version: 61.0.3163.70, beta build
Platform version: 9765.48.0, beta channel sentry device
M-61 build

Steps To Reproduce:
(1) Sign in
(2) Desktop notifications enabled for Chrome Gmail (through web chrome settings>desktop notifications> new email notifications on).
(3)Ensure new UI notifications landed.
(4) Send several emails to current user from different other user accounts.

Expected Result:
Notification should be shown one by one.

Actual result:
1. One by one chrome notifications are not poped up for unread emails, even though this option is enabled from Chrome Gmail settings.
2. Sometimes I see single Gmail chrome notification. So, chrome gmail notification is inconsistent.
3. ARC Gmail notification is shown for few unread emails. But, the notification content doesn't inform about all unread emails.