Hello,
one of the authors encountered a strange issue while he was trying to insert an image into an Image block, he was not able to browse Media Manager clicking on the "browse media" button.
When he put the mouse pointer on the "browse media" button the pointer doesn't change into an hand, it remains a simple arrow and the caption showed is "No file selected". I attached a picture.
I suggested to try with another browser but the problem was not solved.
I had no problems on my device when i logged myself as that author.