TVline have the inside scoop that neither Victoria Cartagena or Andrew Stewart-Jones will be returning as a regular next season. Although, it is not said whether they are being dropped completely or will just feature in small recurring roles.
"Neither Victoria Cartagena nor Andrew Stewart-Jones (AKA Montoya and Allen) will return as regulars. Meanwhile, though Michael Chiklis is coming on board as GCPD Captain Nathaniel Barnes, Zabryna Guevara, who plays Captain Essen, is still a series regular — and in fact will play a key role this season."
The last time we saw Montoya and Allen was around the midpoint of the first season, so it doesn't come as a surprise that both of them are being dropped as regulars.