Weird "flash" before Fotorama Slider appears, Fotorama 4.4.9

Hi,
I am working on a new wordpress website. The installation is fresh.
I am trying to use Fotorama.
Strangely, a weird “flash” appears on the front end when loading the gallery post. It looks like the regular WP gallery (3 columns thumbs) is showing up for a brief second, and then Fotorama appears on top of it.

SEE VIDEO OF THE BUG:
https://dl.dropboxusercontent.com/u/5840419/fotorama.mp4

I tried various combo, but I cannot figure out why it does this flash. I looked on Youtube for a demonstration of Fotorama Plugin and it doesn’t do this flash at all.

Any idea how I can fix this?

Thank you!

NOTE: I tried it on WP’s basic Twenty Fourtneed Theme, and Clippy Theme (a temporary theme I use during testing.).

https://wordpress.org/plugins/fotorama/