Sierpin's Fractal Tree bug

Sierpin’s Fractal Tree unique spear has most likely a bugged interaction with Sentinel’s Javelin skill.
When the bug occures, skill does no damage, no additional spears appear and during animation of the attack, spear disappears right before the enemy which looks like it reached the target.

Same interaction can be observed using the node that splits projectiles instead of penetrating in the javelin tree