Push notifications delayed when inboxes are unified.

Hi, When my inboxes are unified I see notifications get delay, and When I turned them back to individual inbox view I see notifications delivered at standard interval.. I'm on Android, simply configured Gmail and outlook for Thunderbird.. Sometimes i get delayed notifications - don't know why ?? Sometimes say Microsoft incoming server fetched failed - like that similar it says... How can I get the notifications at right time.. What would be the settings i should make.. Lately I found that each folder should be configured like [sync to be off] [push to be enable].. I've done that... What else in that menu we should make on/off . [attached screenshot] I just thiught to have email notification delivered on right time.