Sometimes the screw in bushing on their Grover Rotomatics or shaller gears gets a little loose and the washer vibrates, which can sound like it’s coming from inside the body.
I used to own a Martin om28 I bought new back in around 2015. I've since sold it. But the binding on that one peeled away from the waist area like crazy. Apparently Martin had experimented with new binding glue in 2014 or so. For such an expensive guitar the quality control was a joke really. My D28, which I bought new in 2008, had some minor binding problems...nothing like the om28, where the binding just seemed like it was held on with spit. I used Titebond to repair it the first time. But it didn't last. I had to use something stronger in the end. Titebond is at its best wood on wood, less so binding on wood.
It’s not the glue, it’s the binding. Traditionally Martin used Cellulose Nitrate binding. Around 1990, ( I’m not sure of the exact year) they switched to PVC binding. The older celluloid binding glues with an acetone based glue, think of model airplane cement, which melts the binding together creating a molecular bond. Once it’s glued on the guitar it’s pretty stable.
I never got with the rubber band method of gluing binding. We use binding tape. The best glue for bindings is actually superglue, which is what we have used since the 80’s for most bindings and inlays. I think Heritage is using the same type of PVC binding that Gibson uses.
I don't doubt it. I have read though that in around 2014 Martin experimented with a different binding glue. Probably read that on the Acoustic Guitar forums. If that's true then the problems with binding were probably compounded and made worse in addition to their issues with the different actual binding material you mention. I also do not doubt your comments about Martin quality. That om28 I was talking about cost me a literal bomb of cash and while it appeared very, very well made and looked a gorgeous guitar, it had issues...the binding I mentioned and other things. For the money paid it should have been 100x was it was. Sad but glad to have sold it and got most my money back after owning it 6 or 7 years.
Interesting to see how long the Titebond lasts on the binding. Might be fine, might not. I tried Titebond initially and found it didn't last more than a year or two. I ended up having to go some kind of super glue route. Can't recall the name of the glue but after looking into it a bit it seemed the better option for binding was some kind of super glue. Since I used that the binding has been set like a jelly.
Titebond doesn’t work great with slick plastic. If I needed to use titebond or Hyde glue to glue any kind of plastic binding then it’s imperative that you scuff the inside surface to glide the glue some grip or it will just peel right off after awhile. In a new guitar, superglue is far superior for this application. The problem is it’s very tricky to use it on a finished guitar without creating a cosmetic mess. If you drip it or get it on the finish it can be real hard to clean up. I use it constantly in my shop, along with titebond and Hyde glue.