instrument code P channels not calculating responses

Channels with instrument code P (DP?, GP?, etc) are being treated as SOH and responses are not being calculated. After defining a station with a Magseis Fairfield node and channel names DP? or GP? (as the two I have tested), Calculate Responses gives the following output in the command line:

XX XXXXX DPZ SOH SOH channel not found in {} XX XXXXX DP1 SOH SOH channel not found in {} XX XXXXX DP2 SOH SOH channel not found in {} XX XXXXX GPZ SOH SOH channel not found in {}

Using HH? for the channel names instead of DP? results in responses being calculated as expected.

OSX Yosemite 10.10.5 Nexus version: the most recent one shared with the Data Group via email last fall, maybe 2019.219