Patricia Gibson had been facing claims she made inappropriate comments to an SNP staffer in a Westminster bar in January 2020.
She has always strongly denied the allegations.
They were probed by the House of Commons and initially upheld, but it is understood they have now been thrown out on appeal.
The decision by an independent expert panel will be published on Thursday.
It comes after SNP MP Patrick Grady was found by an independent investigation to have behaved inappropriately towards a member of staff at a party function in 2016 and suspended from Parliament for two days.
The party also withdrew the whip from the MP until he had served his suspension.
However, the SNP’s handling of the complaint against Mr Grady attracted criticism, most notably from the victim himself, who said he had been made to feel as though it was his fault and his life had been made a “living hell”.
In a statement in the Commons last week, Mr Grady said: “I am profoundly sorry for my behaviour and I deeply regret my actions and the consequences.
“Any breach of the behaviour codes and associated policies risks bringing this House into disrepute and will cause the stress and upset not just for the complainant but to the wider parliamentary community.”
Addressing the Speaker, he said: “I give you and this House my firm assurance that I have learned significant lessons through this process and a firm undertaking that such behaviour on my part will never happen again.”
The SNP has been approached for comment in relation to Ms Gibson.