Putting a proposal together and asking colleagues to support it isn't a bad thing in itself.
However the proposal cannot remove the chairman or the vice chairman of the council.
Ring the clerk and ask who out the proposal in, and ring that councillor and ask them what it is about. What reason have they not to tell you.
Ideally, however, any such motion in the agenda should name the councillors, as otherwise it could be argued not be valid as the councillors concerned would not have had due notice of the agenda.