Why are my active merchant listings automatically delisting after 12-15 months?

I have been selling on Amazon for 5 years now. Have a 15,000 square foot warehouse so we have a lot of slow selling inventory that we sell out of the building if FBA isn’t feasible for sell-through rates. When an active merchant listing is listed for more than 12+ months, they just get entirely wiped from my account, so I can’t look at sales history or anything on those items. It has to be made with an entirely new SKU and we have to re-list everything, costing a lot of money in additional employee costs. I have made several support cases over the years with no help or solutions for this issue. There aren’t any settings in our account that should make this happen.

Has this happened to anyone else and does anyone have a solution or answer to this problem? It’s also making taxes harder since we claim inventory over a year old for inventory-write offs and this just makes everything more difficult to keep track of.