bitcoind – Why does bitcoin core has to reindex the chainstate listing in some circumstances?

I used to be studying that some individuals had been capable of migrate their outdated index directories to a brand new machine and never needing to reindex.
However for me it says that the chainstate listing is “corrupt”, though these recordsdata had been working simply high-quality on the outdated node. I believe that it is not likely corrupt, however that bitcoin core is not studying it accurately.
What makes this migration course of not work for some individuals, like myself?
Simply to be clear, on the brand new {hardware} I deleted the next 3 index directories, earlier than copying the recordsdata to them from the outdated {hardware} (utilizing rsync command)

bitcoin/blocks/index/
bitcoin/indexes/
bitcoin/chainstate/

And utilizing reindex-chainstate=1 within the config file takes a very long time (already been 3 days and it is nonetheless not midway achieved).

There’s most likely one thing that must be set for the chainstate listing to be suitable on the brand new node with bitcoind.