Second Fear Period
Many dogs will show a rise in their level of aggression (reactivity) during this time. They may become protective and territorial. Incidents of teenage flakiness may recur.
6 to 14 months
In large breeds this period could extend longer since it is tied to sexual maturity. Incidents may occur more than once.
Corresponds with growth spurts. Therefore it may happen more than once as the puppy matures.
May suddenly be apprehensive about new things or shy or timid of new people or situations. Most of height growing is over, but pup will start to fill out over the coming year.
Puppy begins to mature sexually: male begins to lift leg, and female has first heat period anywhere from 6-12 months. Puppy coat being replaced by adult coat, starting down the spine.
This is a fear of new situations and are handled with the utmost patience. The dog is encouraged to work it out on his own. If anything, it is better to ignore the whole situation than to reinforce the fear by praising the dog or petting him while he is afraid. When you "reassure" a dog with pets and "it's okay, fella", you are telling him it is okay to be frightened and you are creating a potential problem.
If your puppy appears apprehensive, avoid confrontation.
Build confidence through training.
Avoid any potentially overwhelming circumstances you cannot personally oversee, such as shipping your pup in the cargo bay of an airplane.
This from the training school we attend
Developmental Stages
I would suggest something like this...
(happy voice)
"Let's go look. No Biggie"
Then shrug & walk away or distract with something fun.
This way he knows you have his back but at the same time whatever frightened him is really of no consequence. No coddling though.