The lateral forces are in any direction that aren't rotational or vertical, so the distance doesn't matter. What does matter is how much centrifugal imbalance there is from damage to the rotor blade. The helicopter body is set to orbit in opposition to the offset of the rotor CG. If that offset is 0 there is no shaking.
I doubt the blade itself is strong enough to kick-back over it's length**, but losing 2.6m will lose a lot of the most heavily accelerated mass and that will result in an unbalanced tension load the blade is certainly strong enough to withstand.
**This is in contrast to the kickback of hitting a baseball with a bat far off the "sweet spot" and having the resulting vibration hurt the batter's hands. In that case the bat is very sturdy compared to the squishy hands. The helicopter situation is like spinning while holding two heavy buckets by strings and cutting one of the strings. The person doing the spinning is very likely to fall over.