I have owned a Olea europea since last August. It was originally designed by Bonsai Master Roy Nagatoshi of Fuji Bonsai and I made a seamless transition from the past owner in California to Northeast Florida. During this time, there was no notable leaf loss.
Since March, I've noticed leaves turning brown one at a time and branch die back where they fall off on 3-4 areas of the tree. I cut back on watering during the winter months and increased again based on how the soil feels as the sun moves north (faces south on a screened porch).
The tree is estimated between 35-40 years old and any loss is a loss that didn’t have before.
A couple other notes:
1) It was repotted in February 2017.
2) Fertilized with 1 teaspoon of 11.11.11 one week ago.
3) I have watered it everyday for the last week and drained in the event it may have been too dry.
4) I have not used any pesticide/fungicide to date.
5) I’ve read the general advice available on BE.
However.....any solid advice would be appreciated.

What did the bonsai master that created the tree say?

Personally, i would not keep it indoors for any lobger than absolutely needed for frost protection. My olives moved outdoors in early april already.

As I mentioned in my post, I live in Florida and it has been on a screened porch and positioned on the south facing area of the porch.

Have you asked "Roy" yet? He should know the plant.

I have not. I didn’t contact him because I did not purchase the tree from him.