CP1 and (to a lesser degree) CP2 have been slowly overfilling since early Tuesday afternoon -> I investigated today and observed that the magnehelic pressure gauges which are in parallel with the pump level transducers aggree with the CDS indicated values, i.e., the pumps are in fact, overfilled.  Dewar inspection indicated everything normal, Dewar vapor (head) pressures normal, LLCV bypass valves closed, dewar exhausts flowing normally, pump exhausts flowing normally etc.  
No evidence of "ice ball" buildup around exposed LLCV needle valve valve stem which have prevented full stroke of needle under some conditions in past winters.
Problem coincides in time with undocumented events from about 1pm-2pm local time on Tuesday (power cycling? reboots?) -> Set LLCV to manual mode and 50% open valved-out instrument air at LLCV and did not observe valve stroke??? Used heat gun to thaw exposed valve stem and repeated.  Now valve stroking between 5% open without instrument air present to 50% of stroke when air valved-in.  Repeated thaw excersise with LLCV needle at CP2.->

Conclusion:  It looks like LLCV needle valve valve stem was prevented from stroking closed via ice buildup on exposed portion of valve stem.  This is consistent with current symptom and past history.  The difference in this case is that the ice buildup was not obvious, i.e., no visable "ice ball" this time, but rather, only a thin layer of frost on the valve stem.  Weather conditions persist.  This problem may reoccur, will monitor.