My new sds-100 is doing similar. I just received it from MTC about 2 weeks ago & noticed it stopped receiving about 4 or 5 days ago. I'm too far from Wx channel to test VHF, but it definitely loses the 800Mhz control channels on the state TRS. Doesn't Rx the CC from search either. No pattern to when it fails. It was good all day yesterday, but stopped after being on only a couple hours today. I turn it off & unplug charger every night.
Swapped SD card & reloaded programming today, we'll see if it makes any difference. I'm doubtful. If this doesn't cure it, Ill probably send it back to MTC, if not too late.