Having some weird trouble with a migrated M2 website. I've seen some resources on here, but they all don't seem to be showing the same symptoms.

Migrated a site using the Magento tool - all went well apart from an odd issue with the select attributes not functioning as expected.

If I update a migrated attribute (Say Attribute Value "A" to Value "B"), it will revert to "A" on save.

However, If I create a new product (non migrated) and do the same thing on the same attribute it updates as expected.

I've read that it may be an issue in the eav_attribute table.

For reference, this is one of the troublesome attributes (which were also migrated):

*************************** 1. row *************************** attribute_id: 595 entity_type_id: 4 attribute_code: type attribute_model: NULL backend_model: NULL backend_type: int backend_table: NULL frontend_model: NULL frontend_input: select frontend_label: Type frontend_class: NULL source_model: Magento\Eav\Model\Entity\Attribute\Source\Table is_required: 0 is_user_defined: 1 default_value: is_unique: 0 note: NULL 

Compare that to a test attribute I created after migration:

*************************** 1. row *************************** attribute_id: 1212 entity_type_id: 4 attribute_code: test_select_attribute attribute_model: NULL backend_model: NULL backend_type: int backend_table: NULL frontend_model: NULL frontend_input: select frontend_label: Test Select Attribute frontend_class: NULL source_model: Magento\Eav\Model\Entity\Attribute\Source\Table is_required: 0 is_user_defined: 1 default_value: is_unique: 0 note: NULL 

There's no difference in the set up, so the backend_model issues I've read about don't seem to apply here.

Other issues I've noticed:

In debug.log, there's a bunch of these errors:

main.WARNING: Attempt to load value of nonexistent EAV attribute '575' for entity type 'Magento\Catalog\Api\Data\CategoryInterface'. [] [] 

Also, I can't for the life of me get these attributes to load in layered navigation. I would assume it's related to the above issues.

Anyone out there who's able to help at all?

Cheers