Matthew Bair (born June 2, 1987), known by his stage name Matthew Koma, is an American singer, songwriter, DJ, and record producer. Matthew Koma is one of the writers behind numerous hit songs, including Zedd's "Spectrum," and Grammy Award-winner "Clarity," also with Zedd.
Matthew Koma has collaborated with Zedd numerous times
The context says that Matthew Koma has worked on “Spectrum” and “Clarity” – both by Zedd. 
The system did likely not interpret the world ‘numerous’ as being more than one. It is a synonym for multiple, meaning more than one. 

( z1 collaborate :ARG0 ( z2 person :name ( z3 name :op "Matthew" :op "Koma" ) ) :ARG1 ( z4 person :name ( z5 name :op "Zedd" ) ) :frequency ( z6 numerous ) )