On 2/14/2022 1:00 PM, Stefan Monnier via Bug reports for GNU Emacs, the 
Swiss army knife of text editors wrote:
>> Looking at my original patch again, this value is already cached as a Tramp
>> connection property named "home-directory". If the code were changed to set
>> that connection property in a more-appropriate place, and
>> `tramp-handle-abbreviate-file-name' simply *reads* that connection property,
>> then I think that should resolve this issue.
> 
> Sounds like it,

I've only lightly tested this patch, but I think it should resolve the 
issue. It only sets the "home-directory" connection property when a 
connection is already established. Otherwise, it just uses the cached 
value (if any).

Maybe there's a cleaner way to do this though; opportunistically setting 
a connection property like this seems like something there might be a 
special function for in Tramp, but I didn't see one after a bit of 
looking so this is what I went with.