Incorrect Sampling Rate

All, I have been experimenting with the Realtek dongle and am noticing some strange behavior. There is one sampling rate that I can not seem to get to match up with the number of samples that I'm receiving asynchronously. Specifically, when I try to sample at 514 kHz, I receive samples at approximately half this rate. Has anyone experienced something similar? I've tried looking through the Osmocom driver but everything looks good and it's really odd that everything looks good for other sampling rates. Just for reference, when I run rtl_sdr, I get the following device information: Found 1 device(s): 0: ezcap USB 2.0 DVB-T/DAB/FM dongle Using device 0: ezcap USB 2.0 DVB-T/DAB/FM dongle Found Elonics E4000 tuner Any help would be appreciated! Thanks, Peter