New
#11
I installed 10120 in a new Hyper-V VM yesterday, activated it with the generic key and upgraded it to 10240. It showed fully activated (with no expiry) in slmgr /dlv, slmgr/xpr and winver.
I then linked it to my MS account and upgraded to 10525 through windows update and it now has an expiry date of 7/16/2016. Almost the same as you - could be timezone as mine expires at 01:59am. Seems 10525 has an expiry (and a watermark) whereas 10240 doesn't.
Presumably the machine (virtual in my case) is still registered on MS servers (as it was activated before).
Hopefully there will be another build before next July anyway