I've had some cgminer stability problems last few days and got lots of "none" blocks that never resolved to an amount -- thought was due to cgminer.  Switched to bfgminer on 11/26, running solid since, but still getting the occasional "none"

20966    2013-11-27 15:00:33    0:29:21    Processing...    271779    25.09968134    97 confirmations left
20965    2013-11-27 14:31:12    3:28:41    Processing...    271776    25.09335376    94 confirmations left
20964    2013-11-27 11:02:31    0:52:05    157007156    42896    0.00409060    271761    25.03167140    79 confirmations left
20963    2013-11-27 10:10:26    1:06:26    416339194    102847    0.00324965    271753    25.05967676    71 confirmations left
20962    2013-11-27 09:04:00    2:07:31    616134876    none    none    271745    25.04038353    63 confirmations left
20961    2013-11-27 06:56:29    5:38:43    1643271777    none    none    271726    25.24489311    44 confirmations left
20960    2013-11-27 01:17:46    2:30:34    736466853    174247    0.00580112    271685    25.01920044    3 confirmations left
20959    2013-11-26 22:47:12    1:06:40    327605438    77621    0.00583897    271671    25.45945221    confirmed
20958    2013-11-26 21:40:32    5:47:49    1701230114    459959    0.00400610    271666    25.21426441    confirmed
20957    2013-11-26 15:52:43    0:02:35    12301112    6300    0.01227533    271627    25.10929891    confirmed
20956    2013-11-26 15:50:08    2:06:37    621115370    68172    0.01158849    271626    25.31762960    confirmed
20955    2013-11-26 13:43:31    4:16:28    1269260019    none    none    271612    25.06672930    confirmed
20954    2013-11-26 09:27:03    6:10:40    1798179211    413442    0.00000000    271587    25.35120125    confirmed
20953    2013-11-26 03:16:23    2:33:55    734657898    265785    0.00921901    271550    25.04570732    confirmed
20952    2013-11-26 00:42:28    0:18:33    88716980    27388    0.01160630    271525    25.19391657    confirmed
20951    2013-11-26 00:23:55    0:06:57    32811214    none    none    271523    25.01478660    confirmed
20950    2013-11-26 00:16:58    0:21:52    104018863    none    none    271520    25.00301320    confirmed
20949    2013-11-25 23:55:06    2:39:44    762343487    none    none    271516    25.13234146    confirmed
20948    2013-11-25 21:15:22    0:17:50    83955229    none    none    271499    25.05621381    confirmed
20947    2013-11-25 20:57:32    11:09:06    2147483647    536259    0.00000000    271496    25.09004834    confirmed
20946    2013-11-25 09:48:26    0:33:53    159862999    none    none    271416    25.20706472    confirmed
20945    2013-11-25 09:14:33    0:57:03    268354936    none    none    271413    25.25596349    confirmed
20944    2013-11-25 08:17:30    1:36:32    454006445    216742    0.00474413    271406    25.25688233    confirmed
20943    2013-11-25 06:40:58    1:16:19    357469243    168759    0.01110069    271392    25.03015945    confirmed
20942    2013-11-25 05:24:39    4:54:27    1386589555    406404    0.00000000    271378    25.04423068    confirmed
20941    2013-11-25 00:30:12    1:33:46    442803138    81319    0.01159345    271348    25.17870377    confirmed
20940    2013-11-24 22:56:26    5:27:43    1557705970    980    0.00000000    271337    25.05226491    confirmed
20939    2013-11-24 17:28:43    2:05:27    591953516    259643    0.01121454    271292    25.11640732    confirmed
20938    2013-11-24 15:23:16    1:40:41    474424287    106782    0.01343919    271274    25.04499037    confirmed
20937    2013-11-24 13:42:35    0:37:25    174694085    none    none    271267    25.08234628    confirmed

EDIT:  Following Processing/none blocks just resolved to an amount
20966
20965
20962
20961