Over encumbered ally damaging building

Game mode: [Online]
Problem: [Bug]
Region: [EU] 1143 official server

155% over encumbered clan member was damaging Black-ice reinforced wooden fence while he was placing it. Takes 15-40 dmg per jump. Happened in non-raid (!) time. Also works on falling on fence even without being over encumbered. And last test showed that taking damage from being spiked on fence deals to your own fence 20 damage for each spike.
Also found a lot of randomly damaged (20-1000 dmg) objects in house, even on hard accessible for dmg objects (2nd row of walls or ceilings). If there is any rational explanations of this damages? We have to spent around 100 reinforced steel daily to repair house without being raided.

Steps on how to reproduce issue:
1.Become over encumbered
2.Jump on Black-ice reinforced wooden fence or even near it
3.Check dmg with repairing hammer
4.Fix it and jump again