A Switzerland-based staffing buyer, Aryzta AG, is struggling with a bakery operation it owns in the US after losing 35% of its contingent workers earlier this year because of missteps at a staffing provider.

The Chicago Tribune newspaper reported the company said challenges remain as it works with its new workforce at the Chicago facility that makes baked goods for fast-food chains such as McDonald’s and for supermarkets.

Aryzta’s comments came as it announced results for its fiscal first quarter ended Oct. 31.

The company had earlier described the incident with the contingent workers in its annual report filed for its fiscal year ended July 31, 2017,  when it said a US federal audit of its third-party labor agency found inadequate documentation, resulting in approximately 800 experienced workers leaving its business during the fourth quarter of its fiscal year.

“By merit of these employees being agency workers, Aryzta did not have the ability to verify documentation of these workers, and the immediacy and extent of the risk that existed was not known to the board,” the company wrote in its annual report.

However, the workers had significant knowledge and experience of the baking process, and there has been a “significant decrease in the labor efficiency and production volumes, as well as an impact on increased waste levels at these facilities, as a result of this disruption.”

Aryzta noted the operations had been profitable since their acquisition, but incurred losses of 16.3 million euros (US$19.2 million) in June and July.

Aryzta isn’t the only company to have lost a portion of its contingent workforce because of documentation difficulties. The (Memphis, Tenn.) Commercial Appeal reported the Tennessee Highway Patrol arrested 20 workers based on documentation at a logistics company that had used a temp agency to hire the workers.