After wood was installed:
MWDC HV: -1700 V
Halog 241490, Run 2013
MWDC HV: -1400 V
Halog 241495, Run 2014
Doesn't look like it has much effect for the third chamber. The third chamber is already shielded from low-energy charged backgrounds by the Cerenkov and a 1" thick piece of plastic so this was not really unexpected. The impact could still be quite large for the front chambers (to be installed this summer) which have no such shielding.