Chief executive Richard Arnold held a meeting last month with staff to discuss concerns related to the club, according to The Athletic.
The topics ranged from the ongoing 'strategic review' to the club's controversial handling of the allegations against Mason Greenwood and the ongoing investigation into Antony.
However, during the meeting a staff member's concerning complaint about behaviour from male employees towards female colleagues was brought up.
"I have personally witnessed uncomfortable behaviour from male employees at this club to my female colleagues," wrote the staff member in an anonymous letter.
"I’m also very aware of comments that have recently been made public, as well as behind closed doors, by senior executives that suggest an unconscious bias within the club.
"How can you ensure female staff are respected and valued across a club? And what process is in place for female employees to speak up if they feel uncomfortable by the actions or comments of certain members of staff?”
Arnold responded by saying: "Any abusive, disrespectful or sexist language is not acceptable by anyone at this club." And he encouraged anyone affected by such behaviour to report it to their line manager, to HR or a member of United's executive leadership.
The complaint comes amid a turbulent period for the club on and off the pitch. United have been widely criticised for planning to reintegrate Greenwood into the squad, for bringing Antony back into the team and, as reported by The Times, for inviting a former coach who is a convicted paedophile to a women's match last year.
Another staff member complained about the club's handling of the Greenwood situation, claiming that it has led to online and in-person abuse towards women and members of the women's team.
There was also a concern raised about the club's attitude towards their women's team and pay equality.
The question read: "So our women’s team is excelling. It’s our first time in the Champions League this year. Last season, we reached the FA Cup final and 2nd place in the Women’s Super League. However, there is limited promotion for the team and the pay gap which reflects the working staff environment as well.
"The 'All Red, All Equal' motto does not exist within our club’s operations and directorate. Is there a plan to move forward with the quality both on and off the pitch?"
Arnold responded, per The Athletic: "The facts and actions in this area speak for themselves. We’ve invested strongly in the players, staff and facilities for the development of our women’s team and that is reflected in the results on the pitch. And I would encourage everybody to take the opportunity to go and view the facilities that have been built this summer for our women’s team. We’re competitive with or better than almost all of the other leading clubs across Europe and we’re committed to continuing this.
"Investment levels have been significant in the women’s team and that’s something we’ve been happy and proud to do. So I think that’s something that we’ve walked the walk and delivered on our actions.
"The subject of equal pay for players is one that gets raised a lot. And I think the reality currently, in terms of where the economics are of the women’s game, in terms of the TV revenue, the ticketing revenue and the participation fees for competitions, are such that an attempt to equalise pay would result in a collapse in the women’s game because the revenues aren’t there in total, or indeed for the women’s game to support that situation.
"But our job is to grow the revenues so it can be something that is supported over future years. And we’re at the forefront of that. And again, paying and investing amounts commensurate or better than the leading clubs across Europe."