Can't back reference in many2many relation

[StarpTech]

type Store struct {
	Id uuid.UUID `pg:"type:uuid"`

	User   *User
	UserId uuid.UUID `pg:"type:uuid"`

	Name              string `pg:",unique"`
	Slug              string `pg:",unique"`
	Invitations       []*StoreInvitation

	BusinessCategories []*BusinessCategory `pg:"many2many:categories_to_stores"`
	Users              []*User             `pg:"many2many:users_to_stores"`

	CreatedAt time.Time
}

type UsersToStore struct {
	StoreId uuid.UUID `pg:"type:uuid,pk"`
	Store   *Store

	UserId uuid.UUID `pg:"type:uuid,pk"`
	User   *User

	CreatedAt time.Time
}

type User struct {
	Id               uuid.UUID `pg:"type:uuid"`
	Email            string    `pg:",unique"`
	Username         string    `pg:",unique"`
	ExternalAccounts []*ExternalAccount
	Stores           []*Store `pg:"many2many:users_to_stores"`

	CreatedAt time.Time
}

Get all Users from Store perspective works

h.db.Model(&store).Where("user_id = ?", claims.UserId).Relation("Users")

but getting all stores from user perspective fails

h.db.Model(user).Where("id = ?", userId).Relation("Stores.*").First()

with the error pg: model=Store has no column=\"user_id\"" but the resulting query works! I tried several other combinations, read the examples but I have no idea why it failed.

It's very similar to https://github.com/go-pg/pg/issues/1422 but I don't find out the exact solution.

any idea?