Simply the act of asking you to come in after hours, for a job related task that is valid on it's face is not enough to establish sexual harassment. I understand that it gave you pause and was not the most logical request, but who ever accused bosses of being logical.
Protect yourself, but don't endanger your job. Document this, have a consultation with an attorney, write an affidavit and notarize it to preserve the date. Then when he steps over that line, sue.
Every legal matter is fact specific, and there are often nuances in every case. This is intended for comment only, and does not create an attorney client relationship.
You may want to consult with a local attorney with respect to state law and whether the conduct rises to the level of sexual harassment, but, based on federal law, and the facts you have presented, it does not appear that there was any sexual harassment simply based upon your boss's request that you perform legitimate work after hours, whether or not it could have been done from home. If there is more to this, and there were sexual comments, suggestive comments, staring, etc., then you should absolutely speak with a local attorney, as, in that situation, there may be a claim.
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