Hit It Rich team is aware that Coffin Multiplier are mistakenly appearing after Free Spins are played.
By default, Coffin multiplier should not be appearing after a Bonus Game as multiplier is not intended to be applied, as outlined in the Game Pay Table.
We apologize for any inconvenience this may have caused, but are happy that you are not loosing due Coins is this case, in fact, there. For this reason, our customer service team will not be able to credit you additional Coins. We will have this issue fixed in our next update to the app. Thanks for your patience!