Does mixing wood sanding dust with epoxy effect the cure time? I guess I should say does it increase the cure time?

I drilled some over sized holes for recessed deck fittings and am filling them with epoxy mixed with very fine sanding dust (to later re-drill a smaller hole). 2tbs of resin, 1tbs of hardener, mix very very well then adding dust to a bit less than a peanut butter like consistency..

Filled the holes and let it sit for 24 hours. It got to a semi tough rubbery state, certainly not hard like epoxy should be. Maybe I'm just being impatient but I drilled/cleaned out the rubbery stuff and made another small batch of goop, triple checking my mix ratios. The second try seems like it's setting up better but it's still been in there for 8 hours at nearly 90 degrees and still a rubbery state (not sticky, feels like a bouncy ball kind of rubber).. Perhaps it just needs more time?

I thought maybe my epoxy got contaminated somehow after the second try so as a test, mixed up another small batch. Same measuring method (calibrated cups), same amounts, same mixing, but left out the sanding dust. Just left it in the cup and watched. Within 10-15 minutes it got hot enough to nearly melt the cup (was smoking a little even) and was solid in 20-25 minutes... So it can't be the epoxy, and 99.99% sure it's not my mix ratio twice in a row...

I've used the same epoxy for this entire project and nothing has taken this long to get tack free even in way cooler temperatures.. The only difference is the wood dust in the mix.. and it's a hole not fiber cloth..

Any thoughts?

P.S. I used the same stuff to glass the inside of my hull this afternoon (well after I filled those holes) and the hull is already pretty much tack free/solid in 3 hours.