Hi Kassim,
Thought I would jump in to add my observations.
Here is my set up:
Mac Mini, OS/X 10.10.5, Safari 8.0.8 (10600.8.9), BB Pro 1.6.4, Genesis 2.2.3, Metro Pro 2.0.1
No problems adding new BB content or editing existing BB content.
And I still have DWB installed, but all I did was upload the latest Metro Pro and activate it.
Additionally, I still have Genesis Dambuster installed and active.
Just to check, but are you using the latest Genesis 2.2.3 and the latest Metro Pro 2.0.1? If so, I may suggest there is an issue with your server configuration. Also, as you did not provide a URL, what server is the site running, Apache or nginx?
Cheers!
Lyle