Interpretation of MANCOVA with multiple covariates added simultaneously, SPSS


I'm interested in how to interpret Mancova analysis with multiple covariates added in the covariate (s) box. These covariates are age and education level. Mancova shows that both of them are significant when I add them together: see pictures 1 and 2.

But when I add only one of them as a covariate, Mancova shows that neither of them is significant: see pictures 3 and 4.

Also, it is worthy mentioning that these variables are statistically significantly correlated: see picture 5.

Thanks for your attention