Just got a weird call from in-laws skilled nursing facility. What could this mean?

Sounds to me like some kind of scam or prank call. The caller basically said she is required to inform you of something she cannot inform you of. That is a nonsense statement. Call the facility and speak to an administrator to be sure, but I bet it’s nothing.

In our city it is public knowledge which facilities have Covid. It is not a secret! It is broadcast on the daily news and written up in local newspapers.

This whole thing is so weird like a twilight zone moment.

Go there immediately or call and ask for the head n urse, her doctor & demand to know what is going on!!!!!!!!!!!!!!!!! Dr Jack Grenan

Read the replies people. The OP already got to the bottom of things. An employee tested positive for COVID. There’s no scam. There’s nothing out of the ordinary going on.

Sorrynotsorry: I am glad that you got the answer that you were looking for, though the facility handled it in a rather bizarre fashion.

A cryptic message like this would send my anxiety meter through the roof. However, in their odd way they were trying to let people know something. My mom was in a 5 star rated NH for rehab and she developed a stage IV pressure wound they never told me about. I was only informed about this when mom was rushed to the hospital by a hospital intake nurse when she developed a bad UTI that led to delirium. In another NH later, an aide dropped mom on the floor while transferring to a wheelchair, but I was there when it happened. I took mom home as I had had enough of NH's and their failures, and she passed away peacefully at home on hospice. I have come to expect calamity when it comes to NH's, probably not a popular opinion on this site...., but I had bad experiences from even 5 star rated ones.
You have a right to know what this call was about and I would contact the administration there.

If you answered the call in person , it seems they should have told you it was a COVID case. If they were leaving a message or voice mail, they are sometimes more circumspect about details unless they know that number is "okay'd" for leaving explicit messages.

Better demand answers from a higher up atministrator

There are security/privacy concerns with messages left on answer machines. Who know who will pick up the message?