Touch the Armos combo and keep holding down the directional key (continuous touching Armos). When the Armos combo sucessfully becomes an Armos enemy, a duplicate Armos enemy appears. That is a glitch.
No duplicate Armos from the same spot in the NES.
Please correct the glitch.
I can confirm that this is in b584. Almost no player would do this since you are pretty much forced to take a hit from the newly spawned Armos, but I suppose it could be quite problematic if you got pushed into a spawning Armos at just the wrong time or something.
Fixed!
I am unable to verify it fixed in ZC due to the crash bug. (Look in this thread.)
Move to quarantined bugs for now.
Confirmed fixed in 626!
Move to exterminated.