Maybe the effects are locked? Check it in rig manager
They are not locked. They can be enabled in terms that that light up but they do not sound. Same thing if I drag one effect from slots 1 and 2 post the stack or before the stack to slot 3 or 4 post the stack. All show up and light up normally on the Kemper Stage and in Rig Manager but you do not hear it in slots 3 and 4.