The https://www.reginfo.gov/public/ website went offline at the end of last week and was partially restored this week. Data was missing after Aug. 1, according to dataindex,us, a collective of data scientists and advocates who monitor changes in federal data sets.

As of Thursday, the website’s landing page said, it was “currently undergoing revisions.” Emailed inquiries to the Office of Management and Budget and General Services Administration weren’t returned on Thursday.

In February, the Centers for Disease Control and Prevention’s official public portal for health data, data.cdc.gov, was taken down entirely but subsequently went back up. Around the same time, when a query was made to access certain public data from the U.S. Census Bureau’s most comprehensive survey of American life, users for several days got a response that said the area was “unavailable due to maintenance” before access was restored.

Researchers Janet Freilich and Aaron Kesselheim examined 232 federal public health data sets that had been modified in the first quarter of this year and found that almost half had been “substantially altered,” with the majority having the word “gender” switched to “sex,” they wrote last month in The Lancet medical journal.

Former Census Bureau official Chris Dick, who is part of the dataindex.us team, said Thursday that no one is quite sure what is going on with the regulatory affairs website, whether there was an update with technical difficulties because of staffing shortages from job cuts or something more nefarious.

“This is key infrastructure that needs to come back,” Dick said. “Usually, you can fix this quickly. It’s not super normal for this to go on for days.”