Please help. BrickWood pre-mixed Refractory Mortar

Hi,
Has anyone every purchased and used of the already mixed Refractory Mortar sold on Brickwoodovens.com website (see attached picture)? When I tried using it, it hardened very fast, within seconds, so much so I could not properly set the bricks. Has anyone else experienced this? Any advice you can share will be appreciated.

Thank you

Joel