Open your stove instruction manual to the floor protection section. If there is no mention of the word thermal, “R” rating, “R” value or “K” value in the first paragraph, your appliance is ember protection only. If it is thermal, look for “R” value of R=.85 or R = 1.6; then you must use a floor protector that is equal to or higher than the required thermal value of the appliance.
Only use a thermal floor protector with a high “R” value (over 2.0). Never use an ember only floor protector.
Most manufacturers can custom build a floor protector to your specific needs. AJ Manufacturing can give you any “R” value you require and build it in a very reasonable amount of time.
Don’t worry, as long as the tile is not loose or falling out, it is just a cosmetic flaw and does not affect the thermal value of the floor protector. If the tile is loose or falling out, then repair it immediately. Contact the store where you purchased your hearth pad and they can walk you through the process of repairing the pad.