Drew, just out of curiosity I checked the AMBC stations in yuor area to see what could interfere on 160M.
I found WURD on 900 kHz, 2nd harmonic falls on 1800
WCHR on 920, 2nd harmonic on 1840
WIP on 610, 3rd harmonic on 1830.
None have very strong transmitter power, 1-5 kW.
There are several 50 kw stations in your area and some mix could cause intermod almost on any frequency.
73 from K8JD, SKCC 1395, Centurion 18, Tribune 12, Band Endorsements; 160, 80, 60, 40, 30M, 20, 17, and 10M
Ham radio is real Radio, CW is real Hamming!