I've got a few Stronghold holds on my unheated shed board. For the first year or so I found they were pretty slick in damp conditions but now they're totally fine. Maybe its something to do with getting engrained with chalk? Perhaps yours would get better with time too?
My problem is resin holds condensing when there's a rapid rise in temperature. In those conditions (like Monday night) I have to climb exclusively on wooden holds,(mix of BM, Crusher, Hardwood, Stronghold and DIY).