3) In what scenarios the data will be present in the DSO activation queue and not in the change log
You said that only record available in the cube, from the 2 records in the activation queue. this could be possilbe that one record would have loaded some time ago into the cube,
the current 2 records, did not generate any change log entry may be due to the reason that, there is a record already in the DSO with same key and date fields, in this case no change log creates when activation takes place.
Please check that one record available in the cube is part of the recent DTP request which you were worring about,