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Did ArXiv trackbacks for MathOverflow stop working again since September 29th 2016?

Did ArXiv trackbacks stop working for MathOverflow, or does the ArXiv server generally suffer from some issues, maybe related to the planned/ongoing modernization of the service?

From looking at the most recent 100 trackbacks, you can see that very few got posted recently (the last one for MO occured on September 29th) and since October 8th the trackbacks stopped alltogether

https://arxiv.org/tb/recent

For example, this recent answer which cites an ArXiv paper did not trigger a trackback

http://mathoverflow.net/a/251687/30967

Does anybody have some insights about what is currently going on with the ArXiv trackbacks? Are there some technical issues or did they reconsider their list of trusted sites and remove MO (and many others) for some reason?

I strongly suspect that the issues are on the ArXiv side if any, even though nobody else seems to be complaining about troubles with ArXiv trackbacks ...