My phone buzzes (twice) but no notification Since maybe a week I have this weird situation where my phone buzzes twice every so often, but there is no notification. It is really annoying. 

I saw some search results suggesting that this is a notification reminder in Accessibility -> but I cant find such an option in that section of the settings.

Others suggested that this might be apps that are blocked from notifications that are trying to create push notifications but I was able to confirm(reasonably) this isnt the case by unblocking all of them.

Recently I updated my phone, and installed Any.do. I verified that it isnt Any.do either.

I am using One Plus One, with Lineage 14.1, and when I say I updated my phone it is to a newer nightly of 14.1.
After using https://play.google.com/store/apps/details?id=com.evanhe.nhfree&amp;hl=en I discovered that all of my ghost vibrates were due to Accu Battery. Some search results had pointed to that but I did not consider because i hadnt made any changes to it recently, but the problem had only started recently.