Interpreting the solution when posterior density plot shows two solution

[ivanlizaga]

Hello all, I' m working with the model and I found one of my mixture samples could not be unmixed correctly or I think this. How could I interpret the result of the posterior density plot when it shows two different proportion for the same source. The chain length selected was the maximum available (extreme) and the diagnostic looks well. What could I do to fix this? Am I correctly interpreting the density plot? Thanks