Marshmallow in cones becoming soggy

We are using a product called Mallowhip from Bakels as the base for marshmallow which is then piped into wafer cones.

The wafer cones are lined with a compound chocolate prior to piping the marshmallow in to them to try and prevent the marshmallow from making the cones soggy.

For some reason sometimes they work fine, other times after a period of a few weeks the cones become soft and soggy and rubberish.

Any ideas on why and how to best resolve this?

We allow the Mallowhip to sit for roughly 3 - 4 hours prior to piping to help reduce the moisture content. Should we let this sit for longer?

The cones are coated with a compound chocolate rather than a pure chocolate. Would a pure chocolate work better?

We then let the entire cone sit for 3 days with the mallowhip inside prior to enrobing the entire product.

Any ideas would be appreciated.