Very strange error

Hello,
We used your software to migrate and until now it seemed everything worked really fine.
However, after applying 2.4.3-p2 to 2.4.3-p3, we have an error. When edditing a product (any of them) we receive an error:
“The stock item was unable to be saved. Please try again.”
[2023-06-19 14:00:34] main.CRITICAL: The stock item was unable to be saved. Please try again. {“exception”:”[object] (Magento\\Framework\\Exception\\CouldNotSaveException(code: 0): The stock item was unable to be saved. Please try again. at /home/user/public_html/vendor/magento/module-catalog-inventory/Model/Stock/StockItemRepository.php:196, ReflectionException(code: 0): Impossible to process constructor argument Parameter #0 [ <required> Magento\\Catalog\\Model\\ResourceModel\\GetProductTypeById $getProductTypeById ] of Magento\\ConfigurableProduct\\Model\\Plugin\\UpdateStockChangedAuto class at /home/user/public_html/vendor/magento/framework/Code/Reader/ClassReader.php:51, ReflectionException(code: -1): Class Magento\\Catalog\\Model\\ResourceModel\\GetProductTypeById does not exist at /home/user/public_html/vendor/magento/framework/Code/Reader/ClassReader.php:71)”} []
I checked many things.
-- Elastic Search: working properly.
-- Indexes: reindex, etc…
-- Scheduling indexes instead on per save.
-- Tried too… INSERT INTO cataloginventory_stock(stock_id,website_id,stock_name) VALUES (1,0,’Default’);
-- Exporting and reimporting database without DEFINERS
…
Could you enlighten us a little bit or let us know where the problem could be?
Thank you.