The "Try Again" button does not trigger randomization in the Memory Game.
Here is a sample content. I've set this to choose 3 out of 9 sets of cards. It randomizes the cards when refreshing the screen but it doesn't when clicking the "Try Again" button.
Issue is reported in https://h5p.org/comment/15257#comment-15257.
Content created in H5P.org
Issue was tested in.
OS: macOS Sierra (V10.12.3)
Firefox Version 54.0.1 (64-bit)
Chrome Version 60.0.3112.101 (Official Build) (64-bit)
Safari Version 10.0.3 (12602.4.8)
"Try again" button should randomize the cards.