If you did not warm the bacon slabs to ambient temp or above, there could be condensate on the meat which when mixed with smoke gives an acrid flavor.... The slab should have had a pellicle formed on it before the cold smoke....
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In my experience, a pellicle can be formed in a smoker at 120 ish in an hour or so with lots of air flow.... or in front of a fan on a wire rack at room temp, once the meat has warmed up to room temp..... Meat that is refer temp, will form condensate which dissolves the water soluble protein based pellicle or at least, makes it difficult to form...... There are no health concerns leaving meat out at room temperature, once cured, for several hours or even a day to form a pellicle... Meat that has been cured and then cold smoked, will often sit at temps in the 50-70 degree range for weeks with no ill effects....
Culinary Institute of America... ...
http://chefsblade.monster.com/training/articles/966-how-to-smoke-meat?page=2
Pellicle formation
Before cured foods are smoked, they should be allowed to air-dry long enough to form a tacky skin, known as a pellicle. The pellicle plays a key role in producing excellent smoked items. It acts as a kind of protective barrier for the food, and also plays an important role in capturing the smoke’s flavor and color.
Most foods can be properly dried by placing them on racks or by hanging them on hooks or sticks. It is important that air be able to flow around all sides. They should be air-dried uncovered, in the refrigerator or a cool room. To encourage pellicle formation, you can place the foods so that a fan blows air over them. The exterior of the item must be sufficiently dry if the smoke is to adhere.
As noted in the pictorials below from Marianski, cold smoke penetrates farther into cool meat than hot smoking.... So, cold smoked products will "appear" to have less smoke... In my experience here also, the flavor is deep into the meat and a rich depth of flavor not experienced when smoke is applied hot...
