I have created a filter to include the question.notice field. It seems to be OK as returned by

https://api.stackexchange.com/2.1/filters/-9xc1l%2Au-JEsf_Q

Then if I want to fetch this question using the 2.1 API and this freshly created filter,

http://api.stackexchange.com/2.1/questions/194812?order=desc&sort=activity&site=stackoverflow&filter=-9xc1l%2Au-JEsf_Q

I get the following error:

{
    "error_id" : 500,
    "error_name" : "internal_error",
    "error_message":"this error has been logged"
}

If I create a filter excluding question.notice from the above filter, no more error.

http://api.stackexchange.com/2.1/questions/194812?order=desc&sort=activity&site=stackoverflow&filter=APXGzZOp5XPM