covMatrix returns buggy 6x6 rather than a 7x7 matrix?

I am trying to debug a problem in the DecayLengthSignificance functor, then noticed something very strange: In this line, the code expects the 7x7 particle covariance matrix (X,P,E). Instead, if I print the matrix to std::cout, I see a 6x6 matrix that certainly does not correspond to the 7x7 cov matrix, nor to its 6x6 (X,P) submatrix: The momentum part seems not right. If I fix the code to use the submatrices 'posCov', 'posMomCov' and 'momCov' then the failures are gone.

@graven, @sstahl, @wmorren, @msaur, @mmulder, @decianm