String Bet Or Real Bet?

Jungleman goes for a raise pre-flop. Patrick Antonius and Venessa Selbst are also in the hand at this point. The way Jungleman moves his chips forward into the pot in this hand instantly gets call a "string bet" by Selbst. He then gets immediately called by Antonius before anyone has a chance to blink.

Do you think this it was a genuine mistake by Jungleman when trying to move all-in? Should have Antonius waited for a clearer bet before reacting with "call"?

https://www.youtube.com/watch?v=XX5sL70iJ34