Windshield Wipers

Hold on a minute. If you can hear the separated linkage moving with the right pivot post, the linkage is still attached there. It separated ( plastic bushing failure ) all the way over at the left pivot attach point.
To explain, The motor drives the left pivot with one linkage. The left pivot drives the right pivot with another linkage. There are 4 plastic bushings involved. All have the same age and wear.
Taking the glove box liner out will likely happen but that's the easiest step of a proper repair.