Help!

I am running a substrate that gets overmolded with a tpe... the substrate was previously more rigid and now is floppy and flashes easily in the overmold. (The substrate looks like a book end.)

The Substrate material is Lucent PP TPP-0320QU BK2072 , which is a 20% Talc filled Copolymer Propylene, with a UV stabilizer.

I am trying to pinpoint this issue to a material lot change, but not 100% sure as yet,...... in the meantime has anyone seen this as being a possible processing effect?

Thanks,
Joel