"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!

Thanks

Craig