Thanks for your question, and thanks for requesting me directly.
If you are a MA resident, you would be taxed on your worldwide income in MA. Therefore, you could take the losses in WA against the income in MA.
However, if you are not a MA resident and are only taxed in MA because you have MA sourced income, you would not be taxed on your worldwide income in MA and would be unable to take the loss from your property in WA against your MA income
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