The portfolio folder has a bug?

Hi,

I am using the portfolio folder to display the pictures of the different collections. Each time my clients access the website for the first time all pictures overlap.
See: https://www.corkspaces.com/spaces/
However, if they land a second time to this page the pictures are loaded correctly.

I wonder if it is possible to fix this bug or if you recommend changing any features.

I am looking forward to receiving your help.