Hello, Dr. Muthen. I have different results from two different versions (v5 and v7.11) of Mplus running an exactly same script with the same data.
From version 5 with 2-class solution, maximum likelihood was replicated and two classes with proportions of .16 and .83 were estimated.
From version 7.11 with 2-class solution, maximum likelihood was not replicated and, in the final solution, two classes with proportions of <.001 and .999 were estimated.
Interestingly, in the 3-class solution using v7.11, maximum likelihood was still not replicated, and three classes with proportions of <.001, .16 and .83 were estimated. Means of I and S factors in the classes with proportions of .16 and .83 were almost identical with that from 2-class solution from version 5.
I think such almost non-existing classes from v7 are some kind of artifact but am not sure what caused them. I also wonder what results are more trustworthy. If that almost non-existing class from v7 is an artifact, how would I check if it's an artifact, and what advice would you recommend to present the result?