Am I correct in assuming that HMAC_DRBG would return different results if I, e.g. first request 4 bytes followed by a request of another 4 bytes instead of asking for 8 bytes at once?
It seems that in NIST SP800-90A chapter 10.1.2.5: Generating Pseudorandom Bits Using HMAC_DRBG first the K and V values are changed, then the requested number of bits is generated (changing just V), and then the K and V values are changed again. Besides that, leftover bits get chucked away as well.
Isn't it a strange property for a DRNG to return different value if
DRNG(4) || DRNG(4) != DRNG(8) if the DRNG is not reseeded in between? Do other DRNG's have the same kind of property?