Random 401 Unauthorized from /auth

Our node job makes several requests to /auth to get a token for each API call.

Starting yesterday, 21 March, /company/time-offs/ responded with a 500 error early into the job. The job continued, then /auth responded 401 unauthorized 9 times - seemingly randomly.

This morning, 22 March, /auth responded 401 unauthorized at random times again, only 3 times.

Any idea what is going on?