Iteration period seems to be wrong after import

Our current 3-weeks iteration in the pivotal tracker started at 22.04.25 (always wednesday). After importing it to the litetracker the iteration there started at 21.04.25. (Btw. the tooltip on it shows somehow a period from 22.01. - 28.01.). Also the start of the next iteration seems to be incorrect. If the current iteration is from 21.04.25 to 11.05.25 the next iteration should start on 12.05.25 but it shows 11.05.25 so it is one day shifted.