The chlorophenols would start to get really foul after about a month in the bottle. When I stopped using chlorine-based cleaners (which I probably wasn't rinsing enough) the chlorophenols lessened so it's definitely possible they were there in the beer after the mash but I didn't have the palette at the time to pick them up.
All I know for sure is once I switched to star-san and using RO water my beers stopped developing chlorophenols.
What you're describing is probably contamination from a wild yeast, not chlorophenols from chlorine or chloramine. Based on what you've said I would bet that your old cleaning and sanitizing regime wasn't knocking out all the competing wild yeast. Any phenolic off flavor that increases over time is due to yeast or bacterial activity.