I have a Lopi Republic 1750 that's about 6 years old. It started last year emitting light smoke out from under it when lighting it. It was coming out of the square opening in the bottom of the stove. It always would stop once the draft got going but it never did this in the past. I fired it up for the first time this year and did the same thing. I took all the firebrick out of and gave it a good cleaning and inspected the stove and saw no issues. It doesn't do this every time but more times than not. Any thoughts??