Every time I press again, I think, the interval is reduced by the value of my new interval setting under the lapse tab (40%). These are relearn cards in the learning queue. Is this intended behaviour? If so, is there any way to stop it from occurring?
That is normal.
One typo: The New Interval will be EQUAL to 40% of the prev ivl.
The logic here is that if you can’t remember it after a short relearn step, the chances of you remembering it after 40% of the previous interval are low.