creepers are spawning in a room which has a lot of light in it and i can kill them

It depends on the placement of the torches.

This bug lacks of how to reproduce it or in wich situations this bugs is. 

here is a link directly to the wiki about light in [minecraft |https://minecraft.gamepedia.com/Light]

Remember the bug tracker is made for issues that affect gameplay based on problems with the code and not errors made by player like not putting torches in correct places of unkowing how certain thing works, this is because your report will be marked as a incomplete 

Thank you for your report!
However, this issue is Incomplete.

Your report does not contain enough information. As such, we're unable to understand or reproduce the problem.
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