We are using PXI 5922 board with Tektronix current sensor TCPA-300.
Today it was found some negative offset about -1.2V in channel 1 (Ch0 was fine) when inputs were disconnected. Moreover, CH1 became much noisy (~ 4 times) then CH0. Self calibration did not fix this issue. Some time after calibration the offset turns to positive +1.2V value. For diagnostic the Software front panel has been used, and only three first voltage ranges were working fine (1.2, 1.0, 0.5V/div), demonstrating offset mentioned above, but other finer ranges caused error 200005 (ADC overload).
It looks like some potential leakage to this channel take place, because short circuit of the input BNC reduces offset significantly, but does not affect the noise.