After checking your account, I can confirm the following. You had held 4 stocks of GME, and you had placed 2 separate orders aiming to sell them - a limit sell and a market sell. What happened with your account is a quite rare situation. Normally, each order you create is pending confirmation from a trading venue where it would get filled. Once the order gets confirmed, if it is a market order, it gets executed when there is sufficient liquidity (at the best available price). If it is a pending order (limit or stop), it gets filled when both the target price and volume find suitable matches.
As far as the sell orders are concerned, normally, once a sell order is confirmed by a trading venue, you cannot place a second sell order that would conflict with the quantity of the already created sell order. What I mean is the following - if you hold 4 shares and place a sell order for 4 shares, you will not be able to place another sell order if a trading venue confirms the first one. Analogically, if you hold 4 shares and you place a sell order for two shares, you will be able to place an additional sell order for only 2 shares if the first one has been confirmed and is pending execution.
In your case, you managed to create a limit sell and a market sell (4 shares each), and they were pending confirmation simultaneously due to the excessive market volatility yesterday. Unfortunately, they both got confirmed, and you ended up 4 units short. Our equity service does not allow the opening of short positions on real stocks, and the system created a buy order to terminate the created short exposure.