Is the offset in the current limit circuit lower or less variable in the TPS40056 compared to the TPS40052? I have been using the TPS40052 in production circuits for years and sometimes I get a board where switching pulses are periodically missing and the output voltage is lower than it should be. It will typically occur when I quickly change loads and go away when I remove power and restart. I suspect that the current limit is in some way turning off the pulses but I can't understand why and how to remedy it. If the TPS40056 is less likely to get into this mode I would consider using it instead.
Lee