I wonder if its just an over seas cost efficient method to use cheap glue for the Epiphone models unlike made in USA models that may use a brand worthy bonding agent. I could use the old saying "You get what you pay for" but that doesnt always hold true anymore.
The inserts are totally different between the Gibson and Epi. The Gibson's are down in the body while the Epi's sit on top of the body. That is probably why you don't hear about it happening on Gibson Birds.