I would only be concerned if the wood platform of the bed is making contact with the dresser. The wood would be stiff enough to stop the slide from going in all the way. But if it's only the mattress making contact, then I would think the matress would give enough for the to come completely in. Assuming it is only the matress making contact, the "clicking" sound the slide motor makes is a good indication that the slide is completely in.
Good luck.
Frank