Hi Uday,
I am not sure why this is happening and since @auto_tlrc is doing the trick just fine I will put this matter on the back burner particularly since we're busy teaching over the coming two weeks.
If you really want to get to the bottom of this now, consider the history of the output volume from @auto_tlrc and contrast it to the steps you've performed. You can also upload the minimum amount of data to reproduce the problem and we'll try to look into once we're all back in normal mode.
cheers
Ziad