Just speculating here - but I very much doubt this was deliberate, no doubt crew change of pants required!
Surface elevation of Lake Tahoe is 6200' AMSL. Average temperature during daytime in September is 25degC. So Density Altitude could have been 9000' or more.
You need a lot of power to hover a heavy bird at that altitude (chalk 2 appears to be in a very low hover, so better placed for ground effect). Is that quite a coning angle on the dipping machine?