continuous breakthrough of CO2 from thermal swing adsorber

[FPCPROCESS]

Any comments about continuous slippage of CO2 from a TSA(thermal swing adsorber)of air separation unit (ASU).
This TSA has 13x molecular sieve , 12500 kg, 3.6 hrs adsorption cycle.
There is an analyzer at the outlet header, bed B is normal, bed A slips CO2 in the range of 0.3 ppm as soon as it comes in adsorption.