OK, after looking at the manual for your receiver, the remote is very similar to the one for my STR-SL7. Since the green power button is *not* a macro on my remote, I can only assume that you learned the command by "pressing" the button instead of "holding" it until the RM-AV3000 finished learning.

When you just "press" the button during learning, the RM-AV3000 captures it as a non-repeating code. During macros, the RM-AV3000 repeats such codes *three* times.

Judging from my receiver, it is blind to infrared commands for a second or so after receiving the power-on command - thus it ignores the AV3000's repetition. However, the unit is still instantly responsive after powering off, so it responds to the repeated commands by turning on again.