Does this violate the Constituion or California's Brown Act?

Our city council has an agenda item next week that would require two council members signatures to put anything on the agenda.

I've never seen this in dozens of boards I cover.

I suspect this all Republican board is doing this because a Democrat is poised to win in November.

Isn't this conspiring to deprive the people's elected representative of a voice? Why shouldn't any member be able to bring an item forward on the agenda for discussion and a full public airing?