looks like it goes back

http://www.complex.com/music/2017/02/history-of-the-beef-between-remy-ma-and-nicki-minaj

While the track caught many people by surprise (including, apparently, Trey Songz), fans who have been paying close attention knew that something was brewing. The relationship between Nicki Minaj and Remy Ma goes back a decade now, and much of it has been rocky.

Minaj's rise in the rap game happened primarily during the six years Remy was incarcerated for (accidently, she claims) shooting her friend. When Remy was sentenced in 2008, Nicki was appearing on mixtapes and street DVDs.