could not edit the previous post here is a possible cause
per the plugin notes
PunkBuster puts restrictions on how often you can request player screenshots. (Max of 3 screenshots in 10 minutes, Requests must be at least 30 seconds apart). Because of this restriction, you are only guaranteed that the first screenshot will succeed in any 10 minute period. The remaining screenshots requests in that 10 minute period may not succeed.
Like i mentioned once the plugin starts issuing the pb_sv_getss command it continues issue that command after every kill. It could be causing "flooding" by issuing the command to often.
I know i have lagged our servers by issuing unban commands to fast.