It will almost certainly be due to the Dawn Phenomenon aka overnight liver dump of glucose which the body uses to start the day. This needs to be considered when doing morning tests.
This is probably Dawn Phenomenon (DP)
It is very common and even for people without diabetes.
Take a look around this site for DP and you will see lots off threads
My liver is exactly the same 4am around 7mmol, 6 when I get up around 9mmol!! pesky DP. It also does the same when I exercise, BG's shoot up, but usually drop back down to acceptable levels within an hour