Steemit Inc has recently released the version 0.20.0 of steemd, the blockchain software. Yesterday, the whole blockchain stumbled and a lot of witnesses started to miss blocks. As the top witnesses started to disable their node, backup witnesses saw their ranking going up. As a result, I was sent more blocks than usual and also started missing two. In order to help spot the issue, I left my node up for as long as I could. After several hours, it has been spotted that there was a bug in the released code.
A patch has been released and I have disabled my witness and recompiling the software to apply the patch. The server is now replaying the blockchain.
As more witnesses are coming back online, the blockchain should get more stable.