Internal shader error on Sprites-Default after loading twice

Using 1.1.7

So this just started happening for some reason.

• I have 2 levels, levels are addressable and also made up of segments that are addressable (they all exist under a folder marked addressable)
• levels contain various objects, sprites, models which reference various materials etc. These are not explicitly set as addressable though. And don't think I need to? How would I set Sprites-Default as addressable?
• loading first level: save level handle and instantiate manually. Graphics loaded correctly, no missing shaders
• complete level, unload handle, load next level
• internal shader errors on Sprites-Default material, lots of objects show up as pink

How can I determine what's causing this? Why is the shader suddenly missing after unloading then loading again

 

as you already noted, this is most likely the same as what's going on over here: https://forum.unity.com/threads/shader-references-disappear-when-released.727148/

No workaround, but the fix should be released within a couple days. If the next release doesn't solve the problem, please let us know.