Pennsylvania state tax return for active duty military couple

My spouse and I are both active duty military (filing jointly on our federal return). My spouse is a resident of Pennsylvania and I am a resident of Washington. We are both stationed together in a state other than Washington/Pennsylvania. We understand that my spouse is required to file tax return in Pennsylvania even though her out-of-state military income is non-taxable; however, is her investment income still claimed/taxed in Pennsylvania (1099-DIV, 1099-INT, capital gains, etc.)? To further complicate the question, our investment accounts are mutually owned so the income is not solely hers.

Thank you for any assistance!