Slashes in ACF block attributes break search + replace

When migrating a site from dev to live, it's standard to run a search/replace tool from the old domain to the new (eg the wp-cli version, or the Better Search Replace function, which both handle serialized data).

However, URLs that are stored in ACF fields for a block don't get replaced correctly.

When I look in the code editor it has something along these lines:

<!-- wp:acf/myblock {"id":"block_60134f136bcab","name":"acf/myblock","data":{"link":"https://www.google.com","_link":"field_60134e9b92143"},"align":"","mode":"auto"} /-->

But in the MySQL database it will have:

<!-- wp:acf/myblock {"id":"block_60134f136bcab","name":"acf\/myblock","data":{"link":"https:\/\/www.google.com","_link":"field_60134e9b92143"},"align":"","mode":"auto"} /-->

The extra slashes stored are what causes the problem.

This does not happen with default blocks, eg if I insert a Media & Text block, it contains a URL in the mediaLink attribute which doesn't have the extra slashes in the database.

No source files or tests are named. Reproduce the shown ACF block migration and trace how its attributes are serialized into MySQL, comparing the escaped ACF block with a default block; done means search/replace updates URLs in ACF block attributes without corrupting serialized content.