Handler_read Increments with Covering Index?

Has anyone noticed that Handler_read_key and Handler_read_next will get incremented even on a query that never reads any rows (i.e. has a covering index)?

I’ve been trolling source and can’t quite find the method before ha_myisam::index_read() is called where a covering index check is performed to prevent row read.

How are you finding this? From SHOW STATUS? SHOW STATUS will itself create a temp table and insert into it, then read back from it.