"Revolving" QPSK Constellation
You are seeing the "Digital IF” carrier assuming you are modelling what you want to implement digitally in VHDL. The sine and cosine blocks together with the multipliers and combiner perform a frequency translation from DC to the carrier mentioned.  Thus the constellation at this point is really not observable as it will be "spinning" at this carrier rate. (The constellation as observed in the upper figure is at DC and to note it appears to be sampled at 2 samples per symbol, which is typical, so it is really every other sample (the ones on the diagonals) that represents the QPSK constellation at the correct symbol sampling locations). 

To observe the constellation you would need to frequency shift the signal back to DC while being careful not to introduce phase and frequency offsets, or shifts in sample timing (a receiver does this with carrier and timing recovery loops so that it can run completely on an asynchronous clock from the transmitter).

(To note, an optional approach is "Zero-IF" where you implement the frequency translation in the analog domain using an IQ mixer (which is the same functional block with analog components)