"context_from_path" not working for new assets and shots on Windows only

I have a show that’s been running for sometime and until this week have had no issue getting context from path for an asset/sequence/shot using :

import sgtk
p = 'w:/jobname/sequences/sequence/shot'
tk = sgtk.sgtk_from_path( p )
ctx = tk.context_from_path( p )

Now, for any new assets/sequences/shots that are created on the show, I can only get a show level context for this path, rather than shot level when using Windows. I have ran tk.synchronize_filesystem_structure() but it makes no difference, old assets and shots still work and all assets, sequences and shots work when the same principal is run using a Linux box.

Has anyone seen this before as I urgently need to get to the bottom of it as my team can no longer render or submit new versions for review using the pipeline.

Any help most appreciated!