Suppose you engage in a long chain of reasoning: you believe that 1) p, 2) if p then q, 3) therefore q, 4) if q then r, 5) therefore, r, 6) if r, then s, etc. You justifiably believe each of these premises, and on their basis, come to justifiably believe their conclusion: z.
The next day, at 7am, while you are eating breakfast, you gain a reason to give up belief in p. So, you give up belief in p.
At 9am, while you are eating second breakfast, it dawns on you that by giving up belief that q, you have lost a crucial reason for believing z. So, you withhold belief in z. We can stipulate that any ordinary human would not have noticed the connection between p and z very easily; it is natural that you would only see the connection a couple of hours later.
It is clear to me that you are not justified in believing z at 10am. It is not so clear to me what the justificatory status of your belief in z is between 8am and 10am. I’m inclined both ways, which inclines me to think that disambiguation is needed. Perhaps I am justified (in the blamelessness sense of ‘justified’) in believing z, but I am not justified (in the evidential sense of ‘justified’) in believing z. However, I’m hesitant to claim that a disambiguation is needed.