I hate when that happens! Based on your user name I had to say that before I offered an answer.
If you are into dunking the rod handle or you fish a lot in all day rain, I suspect that the grip may become loose once the water has time to work on the bond between grip and blank.
I have read many posts here about the best way to make a repair to this. Most I believe involve sawdust and wood glue mixed into a slurry and then worked into the grip to fill the voids. Then a light sanding to remove excess filler back down to the cork.
I have never filled a grip so you better wait for some of our rod & grip builders to reply. What I said is what I think I remember from past threads.
I quote this from Diver Dan
from another thread: "The best thing I have ever found for fill, and I have tried them all, is Elmer's Carpenter's Wood Filler. Indoor/Outdoor in Golden Oak."