I think it is to do with the external acceleration now being treated as local. If you apply a constant acceleration in one axis then rotate your cloth object the 'wind' appears to move with the object.

I originally logged the bug with the sample which was easy to reproduce, literally the most basic cloth example add cloth to a plane in the newest official release. I had tapestries in a castle before 2019.2 with cloth working beautifully and after I updated to 2019.2 all the tapestries went crazy and flew straight up or balled up into what looked like a black hole a combination of whatever external forces I had programmed to give the tapestries a look of airflow down a passageway with whatever odd external force applies randomly to the cloth without any adjustment by myself. According to the bug status they have fixed it in 2020.1 and are working to fix it for the latest 2019 version alpha/beta and release. Crossing my fingers on the next official release update having it fixed. It could be something funky with whatever code segment handles gravity as an external force and that is causing the odd and seemingly random movement of the cloth, which is why people keep referring to the gravity system but whatever the case I'm hoping its thoroughly tested as they are doing updates to make the cloth system better as part of 2019.

Try to reset rotation or set cloth.useGravity = false . The problem is related to cloth gravity.