PackRat and Loaders are offering good advice. If you have a long relationship with a company and they are currently paying you at the pace they always have, no red flag. If they are now changing the game, no matter the excuse it's enough of a reason to make a few phone calls to protect your interests.
I've recently had a few carriers try and request 10 days from receipt of POD and invoice (we have those particular ones at 45-50). We simply declined and will not allow the paranoia in the world right now affect how we conduct ourselves. Besides safety for drivers, shippers and receivers and social distancing, it's business as usual.
Keep well,
Mike