Does chaining random number generators lead to loss of randomness? Assume you chain random number generators, i.e use the result of one PRNG as the seed for the next. What kind of errors can that introduce in the randomness of the numbers generated?
The practice you describe is acceptable and secure.  As long as each of the cryptographic PRNGs has no weaknesses and you use a seed of sufficient size, this is safe.

Whether it is desirable is a separate question.  Do you really have a valid reason why you need to do this?  If not, it's just adding unnecessary complexity and extra "moving parts" that can go wrong somehow.