Cause for nail pops and ceiling cracks

I bought a bank owned house in October and moved in to the house in January. It's a two story house and the house has an elevated ceiling (I think t's called cathedral ceiling). The ceiling had some nail pops and some cracks in the main joint. I had a person come over and have the nail pops and the cracks fixed. The bank had put on a new roof and it seems that the old roof was possibly leaking since it was in pretty bad shape before the bank had it replaced.

After living in the house for about 3 months, I see that some of the nail pops are coming back out in the ceiling. Also, I see some new nail pops and some minor cracks on a different place in the ceiling. I also see nail pops coming up at the joint between the wall and the high ceiling on and front side as well as on the back side of the house.

I had a roof inspector and my original house inspector come over and take a look at the house. They were not able to tell me for sure what's causing the issue. According to the home inspector, it doesn't look like a structural issue since there doesn't seem to be any damage/cracks to the foundation of the house.

One thing that they pointed out that when installing the new composite roof, the installer added vents on top of the roof. Since the house originally didn't have vents on top of the roof, it had vents on the side of the attic. Those vents are still in place. So, according to him, there are too many vents and that I need to block the vents that are on the side of the house. There doesn't seem to be any molding inside the attic though.

Does anyone have any suggestion around what may be causing my issue or any suggestion around where I can get the best possible help to understand the issue better and get it fixed?

How long was the house empty between owners?

Yes you should block off the gable end vents.

There's a good chance that the nail pops were the result from foot traffic on over spanned roof rafters.

Thanks for your response. I am not exactly sure for how long it was empty. But I believe that it was at least for about 6 months. In addition to the nail pops in the ceiling, there are new recent nails pops between the joint of the wall and the ceiling came up just recently though. So, there was no foot traffic in last few months. Also, the house is more than 20 years old. So, it should be done settling by now. Any advice on what issue can be caused by the gable vents if there are vents on top of the roof? Any other suggestions?

If it is fair to beleive the roof was leaking before it was replaced. If it was leaking wood would have expanded with added moisture and as it drys out it will shrink causing nail pops. When we talk about new house settleing , more often it is wood shinkage that we are talking about. Air should enter in the soffet vents behind the gutters and exit the vents at the ridge or close to it. In some weather conditions air can take a shortcut from the gable vents to the ridge vent you will have no air movement over the exterior wall. The whole idea is to carry the lost heat from the exterior wall away from the roof sheeting because if left there it could melt snow on the roof and cause ice dams, roof leak.

If the house was left unconditioned, you may be experiencing what Neal described, wood shrinkage...

I'm not sure if the roof was leaking. But most likely, it was since the neighbor tells me that the roof was in pretty bad shape before it was replaced by the bank. The person looking at the issue told me that if there are too many vents at the top (that is, gable vents + vents that were installed on top of the roof as part of the new roof), the air will not circulate in the attic since air will not enter from the vents that are below the gutters. According to him, it may be an issue since it can cause the air in the attic to be too cold. Is that true?

Also, should I wait it out the summer and see how bad it gets before getting any repair work done? Or should I may be get another opinion on the issue by someone else (e.g., another inspector, contractor or structural engineer)?

The vents are to keep the attic cool in both summer and winter, Close the gable vents, the ridge vents a big step up from what there was.
I would waite some time on the drywall repairs and monitor the bad spots. Outline bad spots with a pencil and number them take pictures so you can see if they get worse. Just in case you have something bigger happening that only time will tell.

I am thinking about getting a drywall contractor over and get an opinion from him about what he thinks the issue may be. If he thinks that it's the wood shrinking that's causing the issue, I'll probably wait through the summer to let it dry completely (and possibly worsen the nail pops/cracks) and then get it repaired after the summer is over.