One of the persistent logical difficulties in discussing filioque is that Latin theology has two senses of the term "consubstantial" and Greek theology has only one. The shared sense is what I would call the absolute sense of consubstantiality; namely, that there are three divine Persons with one divine substance. This emerges immediately in the creature-Creator relation, in which the consubstantial Trinity stands on one side of the divide and creation on the other. The exact metaphysics of the connection across that boundary can vary considerably.
There is a Latin tradition in which the category of relation is used to explain how God can create and act in creation without being changed by it, and that is to say that we are only relatively real to God, which is metaphysically real as a relation in us but requires no real distinction in God as object of that relation. Among other things, this prevents modal polytheism, in which God is really different in various possible worlds. The creature-Creator relation is explicitly analogized to the procession of the Holy Spirit in the context of the filioque by the Council of Florence as follows: "But the Father and the Son are not two principles of the holy Spirit, but one principle, just as the Father and the Son and the holy Spirit are not three principles of creation but one principle."
As indicated by the conciliar statement, this is not the only unique use of relations in the West, and it is the use of consubstantiality in the relational context that continues to be problematic. If absolute consubstantiality is the metaphysical use identified previously, let relative consubstantiality refer to the use of consubstantiality in the relational context. That happens in exactly one place: the relation of the Holy Spirit to the Father and the Son. Because there is no relation of opposition of the Holy Spirit to Paternity or Filiation, the Holy Spirit's relationship "sees" the Father and the Son as a single object, since they are consubstantial where no relation of opposition intervenes. While that concept may be implicitly be used by a number of Eastern Fathers who see the Holy Spirit as the completion of the Trinity, I know of only Gregory of Nyssa explicitly identifying a unique relational property of the Holy Spirit as the syndetikon (bond) of the Father and the Spirit or as the bond of unity between them. And even then, the Eastern authors do not expressly state that the defining relation of the Holy Spirit "sees" the Father and the Son as consubstantial. While some Orthodox Christians will accept the implicit concept of relative consubstantiality, many will reject it outright.
This usage of relative consubstantiality, consubstantiality seen as object of the Holy Spirit's relative property, appears constantly and repeatedly in the 1995 clarification without a word of qualification: