Hard to tell what went wrong here. And you don't have the shader left anywhere?

Unity has confirmed that this is a bug on their end, which will be fixed in a future release

That's a separate issue, which is known and will be fixed

This has now been fixed in 1.26

Not at the moment, no. Can't say for certain when or if it will come

Thanks for the extra info, I'll see what I can do!

What if it goes via a relay node? Variable -> Relay -> all the inputs that you have now

It might simply be the name of the node in that case. What if you rename "var" to something like "my_thing" ?

What if you connect the Variable node directly, instead of via the Get/Set? Does the same issue happen?

I generally don't adapt to beta versions as they tend to change rapidly, but I may have to make an exception in this case. Which shaders broke and what errors did you get?