Presentism, Divine Memories, and Circularity

In A Treatise on Time and Space, J R Lucas - a (sometime) presentist and theist - posits the theory that it is God's memories that ground purported truths about the past (I think Alan Rhoda also subscribes to this view and has a paper on the subject but I haven't read through it carefully yet). There's a bit of trouble for this theory, though, that means such a theory needs to be restated.

First, let's take a step back - when we remember something, what do we remember? I take it that we remember something having occurred or having been the case - that is, that memory presents its contents as obtaining in the past. If we represent the situation as this: 'Memory(p)' the complete content of the memory will be 'it was the case that p'. We can cut out the tech-speak by simply saying 'I remember that such-and-such happened' or something similar, where the sentence falling under the that-clause is in the past-tense.

So if God remembers that p, 'p' is going to be past-tensed. But since it is past-tensed, it is in need of a truth-maker if presentism is true. This is what Lucas's account supplies: What makes it true that p is that God has a memory that p. But now we are in trouble. What makes something a memory in the first place? What makes something a memory that p - as opposed to some other attitude towards p - is that p is true and p's occurrence is responsible for that very memory. Leave aside the second, 'responsibility', clause - it offers its own problems, but I won't go into them here since the problems offered by the first are enough for now. The fact that p is one of the grounds for the fact that God has a memory that p. But, on Lucas's view, the fact that God has a memory that p is itself supposed to ground the fact that p. We clearly have a vicious circle that we somehow must break out of. If we want to keep something like Lucas's view, I take it that the only option is to come up with some other way of picking out the appropriate mental states which are supposed to be doing the grounding work - that is, other than as memories - and in such a way that we do not already presuppose what we are supposed to be explaining - that is, the truth of things like p. I don't know if that's going to be a difficult job or not - but if this sort of view is to be tenable, I think it must be done.