Stranded inventory keeps happening even when inbound shipments are fine, is this a northeast warehouse thing?

Third time this quarter I’ve had units go stranded for no apparent reason. Shipment arrives to amazon, gets checked in, quantities match, everything looks good. Then two weeks later random SKUs show as stranded and I’m scrambling to figure out why.

Already ruled out the obvious stuff. Labels are correct, my 3pl in secaucus handles prep and shiphype has been solid, FNSKU barcodes scan fine when I spot check. Called them to double check and everything on their end is by the book. They confirmed shipment went out correctly and amazon received it, but obviously once amazon checks it in they have no visibility into what happens on amazon’s side. That’s all seller central at that point. Amazon support just gives me copy paste responses about “investigating” and then closes the ticket without actually fixing anything.

I can literally see the inventory in the warehouse, it’s physically there, it’s just not available for sale. Meanwhile I’m paying storage on units that can’t generate revenue and my IPI takes a hit because amazon counts stranded inventory against you.

This was happening when I prepped myself too so it’s definitely not a 3pl issue. Starting to wonder if I need to file removal orders just to get the units back and reship them which feels insane but at least they’d be sellable again.

Anyone figure out a pattern to why this happens or a faster way to get it resolved than waiting weeks for support to maybe do something?