WordPress 5.2

Not sure, what is going on with WordPress 5.2 but during this past week alone, I have had at least 5 different client websites with different themes and configurations show the error ‘this website is experiencing technical difficulties”. At least 3 other websites menus are totally messed up, and under customize, reassign the correct menu to their correct location won’t save. It’s hard for me to isolate the issue as it seems almost random. The website that displayed the error message, i temporarily fixed the problem by downgrading php from 7.2.19 to 7.1.
Those with menu and logo not saving, I still can’t find a solution. This is happening with different themes and different configurations. Finally just few minutes ago, I did a fresh install of WordPress under plesk. Then, tried to login to the admin dashboard… I was surprised to encounter the same error message on a fresh install. Once again, I downgraded php and was able to get WordPress running. On another site…. caldera form simply won’t work after upgrading to 5.2. / error on that is invalid token so form won’t submit. As I said symptoms are random but all centered around upgrades to 5.2. Anyone knows what is really going on? I manage over 50 WordPress sites weekly so this is getting to be frustrating.