Scratching is normal in males and females. Females just do it more due to instincts for egg laying. She is probably gravid. You may want to prepare for that or freeze the eggs if you don't want to incubate them. What are the temps in your tank and how are you tracking them??
I'd probably put the tile back in there if I were you. Loose substrates cause a world of problems. They are obviously breathing it in, there is no disputing that. They are also absorbing it through their vents, they lick everything, etc. It's not good for them. In the wild, there is dirt and loose particles around but they are not constantly contained in a loose substrate like they are in captivity. I can promise you that you will see a problem in the future if you do not change that out. Our rescue project has dealt with a lot of impaction issues in several types of lizards and I ask that you trust me on this one.
As well, I have a strong feeling many people on here will tell you to separate them. I support that you've made your decision in that regard but over-breeding can be fatal. They may not have bred yet, but they will and the male will often get incessant about it. He won't leave her alone. Don't underestimate them, my male waits until I leave the room before he breeds but I breed with purpose and he is not allowed to spend an extended period of time with my females. A breeder friend of mine had a dragon that got its head literally ripped off one day out of the blue due to caging together. They must have had a fight over territory. I never caged mine again for fear that would happen to me. Just something to keep in mind.
