Missing Assembly reference to all packages after updating

[Stroustrup]

after updating from either 2020.1.0b14 to 0b15 or 0b16, unity cannot find references to packages, despite them showing as installed in the package manager and present in the .sln project

tried removing the library folder, no avail

i also get this as the first error

[Stroustrup]

removing the com.unity.ui package seems to have fixed it,
something to do with cyclic references between com.unity.ui and com.unity.ui.runtime maybe

[Stroustrup]

think this is the problem but for beta 15 / 16

also