Yes, since the 4 transmissions on Dec 31, 2015, I have not seen or heard V28. It may be it has terminated activity, or it may have shifted to a time and frequency not yet found.
However, I am not sure I agree with the transmitter being "very low power". I was able to hear the 3277 kHz and the ~3690 kHz transmissions every day here in the Mojave Desert of California. Some days not very strong, other days fairly strong, particularly the ~3690 kHz signal. Comparing that with other Asian sourced signals in the band the power was not low. It may not have been up to Voice of Korea, Pyongyang, signal levels, but it was stronger than some signals of known ~1 kW power.
T!