Gottlieb and Parvizian has a recent paper, Descartes' God is a Deceiver, and that's OK (PDF), whose argument is so absurd that it has to be trolling. A few points:
(1) They say, "God cannot be a deceiver, the thought goes, because God is omniperfect," but already we see here a problem: Descartes doesn't hold that God is not a deceiver on the basis of God being omniperfect, because 'omniperfect' is not a thing for Descartes -- indeed, it is not actually a thing at all. Descartes bases his claim on the idea of God as infinite (i.e., unlimited) perfect (i.e., complete) being; and he does it because he thinks it is conceptually necessary that deceiving involves limitation or incompleteness, because the act of deceiving always involves either malitia (badness) or imbecillitas (feebleness). This is not a quibble, because what analytic philosophers sometimes call 'omniperfection' is not what Descartes means by 'infinite perfect being'.
It's also notable that the authors basically sideline any discussion of imbecillitas, saying it's obscure, focusing entirely on malitia; but this vitiates their entire discussion by leaving out a significant element in Descartes's actual account of deception.
(2) Throughout the paper, the authors confuse deceiving with being deceived. Descartes's position is crucially bound up in his insistence that while we can be deceived, God is not a deceiver. It is because of this that we can know that it is possible for us to know things about the sensible world. If we are deceived about the sensible world, it is because we have freely failed to exercise sufficient caution and method in making our judgments, not because we are naturally unable to do so. Most of the paper is concerned with trying to show that Descartes holds that we can be deceived by our senses; this, despite being blatantly obvious when said of Descartes, is literally irrelevant to the question of whether God is a deceiver.
(3) They give as an account of deception that they claim Descartes would support:
X deceives a subject S if (i) S judges that p; (ii) it’s false that p; (iii) X judges that p is false; (iv) the evidence E on the basis of which S judges that p is brought about by X for the purpose of making S judge that p.
This is not correct; deceiving as Descartes presents it is an act, and notably this definition abstracts from the particular kind of action that X is itself engaging in. However, even if we assume this, it fails in the case of God as conceived by Descartes, because we don't know God's purposes, and therefore we could never be in a position to know that (iv) obtains; what we can rule out, on the other hand, is that God's actions are such as to be indicative of finitude or incompleteness, without which Descartes thinks deception is impossible.
What is more, this account fails to grasp Descartes's concern in the entire discussion of 'God is not a deceiver', namely, that he wants to show that however deceptive the senses (and other faculties) may be, their deceptiveness cannot possibly be indefeasible. This definition is useless for saying anything about the defeasibility or indefeasibility of sensory deceptiveness.
(4) The authors put a lot of emphasis on the question of whether our judgments are violating 'epistemic norms'; this is completely out of place in discussing Descartes, because 'epistemic norms' that apply to judgments are also not a thing for Descartes. What Descartes is concerned with is the freedom of our judgments, whether our judgments are determined by our nature. Arguing on 'God is not a deceiver' that the latter is impossible, Descartes has established that if we are ever deceived it is in every case because we freely did not exercise the care that would be required to find the truth. This is entirely independent of any consideration of what our 'epistemic norms', if any, might be.
(5) The argument given requires that there be two distinct 'theodicies' in the Meditations, the Fourth Meditation based on free will and the Sixth Meditation concerned with sensory judgments (where the authors take the justifying element to be divine benevolence). This is one of those things that is kind of true and kind of false. For one thing, Descartes still seems to appeal to what he has established in the Fourth Meditation in the context of the Sixth Meditation discussions. But the Sixth Meditation is concerned with arguing, as Descartes says, that, where we do not have the time or care to exercise our freedom in the proper way, we will often go wrong because of the weakness (infirmitas, which is a synonym of imbecillitas) of our own nature. That is, the structure is that
if we do not use our freedom to judge only what we clearly and distinctly perceive to be true
then we will often go wrong
--------- not because of any deception on the part of God
--------- but because our nature is finite and imperfect, involving the limitations of the body, such as are inevitably relevant to sensation, especially insofar as the body has to be structured so as to survive and operate in a physical environment.
The body's structures being the way they are so as to contribute to survival and reproduction is important in showing that God's allowing us to have these limitations is not a problem for Dei bonitas (God's goodness, not 'divine benevolence', which is not an exact synonym, and which Descartes could perfectly well have said if he had wanted to say it); but all of this is just Descartes tying up loose ends in his account of how we know anything about material bodies by forestalling a potential set of objections. The whole thing presupposes already that God is not a deceiver as part of the antecedent structure, and also the Meditation IV 'theodicy'. And what it is intended to do is the opposite of what the authors claim -- it establishes that our tendency to go wrong when we just go on sensory experiences is due to weakness in our nature, not God's.
