Transaction Isolation/Unit of Work API addToRelation can not work with one to many relation

I noticed a strange error while using unitOfWork API.
I try to add objects into column which has 1:N relations, but the error shows This operation result not supported in this operation

What I am supposed to do?
Is this a bug?

Can you describe how you’re structuring the operation for which you get the error?

It may possibly be a bug, the transactions support at this point is in the pre-release state.