http://www.perlmonks.org?node_id=475157


in reply to Re^3: Ouch! Each! Reentrant it is not
in thread Ouch! Each! Reentrant it is not

Experimentation proves you right. Interesting. I must have mis-interpreted the perldoc:

There is a single iterator for each hash, shared by all "each", "keys", and "values" function calls in the program.