[atlas] A number of built-ins stopped?

Hi, Both on the atlas webpages as via the api, data for a number of built-ins stop at December 22th, at around 18:00 UTC for all my probes in 4 different ISP’s, all in NL. For instance measurement 1009, ping to a.root-servers.net stopped at that time while measurement 1010, ping to b.root-servers.net continues normally. Also stopped are: #1017 Ping to ctr-nue13.atlas.ripe.net #1012 Ping to d.root-servers.net #1013 Ping to e.root-servers.net #1015 Ping to h.root-servers.net #1005 Ping to i.root-servers.net Any idea what is causing this? Regards, Ernst J. Oud