[ Etymonline for 'count (n.)' ] ... from COM- "with" (see com-) + stem of ire "to go" (see ion). ...
For want of discrimination, I bolded the later 2nd com- prefix, and capitalised the first one.
How and why was a second com- fastened onto
Is the 2nd redundant? If the 2nd is necessary, what does it mean especially?
What are some formal terms describing this phenomenon?