This causes some difficulty when another user edits (or suggests and edit for) a long post with many links, and later I try to review that edit. Since many of the link identifiers will change, the side-by-side markdown diff will contain a lot of changes, and it's hard to see the real changes. For an example, see revision 38 of https://meta.stackexchange.com/a/271127/222298 .
It seems to me that changing existing link identifiers is unnecessary. When adding a link, the editor should not modify existing links. It should only find existing link identifiers like it does now, and generate a link identifier for the new link that is distinct from all the existing ones. I would like to request that you change the editor so it does that.