Question regarding PNAS submission

[mkuch17]

I was wondering if anyone who has some familiarity with the PNAS submission process could answer a question for me. I recently submitted a manuscript to PNAS, and it is currently in the quality control stage. I just checked the status of the manuscript and it says "quality control issue identified." Is this normal, or does this mean that there is a problem that must be fixed before it can get sent to an editor? I imagine if there is a problem, they will let me know tomorrow, but in the meantime, I was hoping someone might shed some light on this issue. Thanks.