i haven’t seen the footage and don’t know what launcher they use, but warheads for the old soviet RPG-7 often do not have such safety feature. especially if they are using scratch-made or modified/repaired/refitted equipment and munitions.

https://www.quora.com/Does-an-RPG-7-ammunition-have-a-timed-safety-fuze-to-prevent-it-from-exploding-close-to-the-launcher