OpenAI isn't a single company. I haven't followed all the details with its structure change/recapitalization, but it's (I believe) a parent sitting on top of an LLC that outside investors like Microsoft hold a large minority stake in.
The rules say that the parent has to report 100% of the LLC's revenue and expenses as if it owned everything and then, at the end, back out the share of the loss that economically belongs to the minority holders.
So $8.84 billion is the whole loss, $3.74 billion is approximately the outside members' proportional share of it, and $5.09 billion is what's left for the parent. Nothing disappeared or was hidden. It's one number presented two ways because two sets of people own it.