mandoc 1.14.5 produces few warnings on usb_parse_data(9f):

Man page format/spelling:
mandoc: usr/src/man/man9f/usb_parse_data.9f:10:2: WARNING: skipping paragraph macro: PP after SH
mandoc: usr/src/man/man9f/usb_parse_data.9f:21:2: WARNING: skipping paragraph macro: PP after SH
mandoc: usr/src/man/man9f/usb_parse_data.9f:74:2: WARNING: skipping paragraph macro: PP after SH
mandoc: usr/src/man/man9f/usb_parse_data.9f:94:2: WARNING: skipping paragraph macro: PP after SH
mandoc: usr/src/man/man9f/usb_parse_data.9f:100:2: WARNING: skipping paragraph macro: PP after SH
mandoc: usr/src/man/man9f/usb_parse_data.9f:133:2: WARNING: skipping paragraph macro: PP after SH
mandoc: usr/src/man/man9f/usb_parse_data.9f:150:2: WARNING: skipping paragraph macro: PP after SH

mandoc produces no warning after the fix, visually it's the same.