Hello,
We have a similar problem with the TPS61070. For power saving, we switch the TPS on and off quite often.
It seems to depend on the slowly decent of the output voltage when the output capacitor discharges.
We'd speed up this discharge by adding a resistor from VOUT to EN, so when our MSP430 turns the TPS off by making the EN low, it also discharges the output capacitor.
When the TPS is on, we have an extra current of Vout-Vin / 10K. (in our case 2.7-1.9=0.8V 0.8V/10K=80uA) Not a nice solution, but the best so far.
Can you give us more information about this problem?
We think it only occurs at specific output voltages or input/output combination. Can you verify under which conditions it happens? So we can optimize our circuit.