She does effectively copy "Tasty", but when she mimics "Cashing In", it doesn't seem to double down on hat effect, causing enemies to drop as much gold as they would without him being mimicked.

Is this intentional? I can see why it might be, since the ability causes a visual change in gold drops, a mimicked version can't add a second layer of visual change and therefor doesn't apply a second gold buff.

If it is NOT intentional and, in fact, a bug, it seems like a simple fix. Just have the ONE visual change but instead have just those grey coins equal the combined buffs from both instances of "Cashing In". Ergo... Gold coins = Base gold buffs, Grey coins = Base gold buffs x Turps' "Cashing In" buff x Mindy's "Cashing In" buff.

Yeah, I wonder what Mindy's really copying sometimes. I know she can't mimic gear only attributes.