In some cases, one cannot achieve a perfect “burst alignment” for TOPS. Burst alignment here means the following:
Say, line no. 100 of the master image comes from burst 1; then line 100 of slave image must also come from burst 1. If it comes from burst 2 you will see noisy lines in the interferogram (because the signals from burst 1 and burst 2 are not coherent).
In most cases, this alignment can be achieved for every line.
In a few cases, you cannot perfectly achieve this, and there will be a couple of lines having a problem of alignment.
Usually, this would only cause a few noisy lines in the interferogram. You can check your interferogram and see if this is true.
If we want to understand what is happening in this particular case, please send in the full log.