Emperors of Soul is a 1994 box set compilation for The Temptations, released by Motown Records. The five-disc collection covers the Temptations' entire four-decade history, from the first recording of The Distants in 1959 ("Come On") to four new recordings by the then-current Temptations lineup of Ali-Ollie Woodson, Theo Peoples, Ron Tyson, and stalwart members Otis Williams and Melvin Franklin.
Otis Williams and Melvin Franklin have been in the band the longest out of the current line-up
The context states that Otis Williams and Melvin Franklin are 'stalwart members' meaning, loyal, long-term etc... and are separated from the other three band members who are not described as stalwart. This means Otis Williams and Melvin Franklin have been in the band longer. The system could likely not understand the use of stalwart in this context. 
( z1 include :ARG1 ( z2 and :op ( z3 person :name ( z4 name :op "Otis" :op "Williams" ) ) :op ( z5 person :name ( z6 name :op "Melvin" :op "Franklin" ) ) ) :ARG2 ( z7 band ) :ARG1-of ( z8 have-degree :ARG2 ( z9 long ) :ARG3 ( z10 most ) :ARG5 ( z11 include :ARG1 z2 :ARG2 ( z12 line-up :time ( z13 current ) ) ) ) )