For an outdoor pool exposed to sunlight, the CC from higher bather load is mostly intermediate compounds that haven't yet been fully oxidized. The largest component of sweat and urine is urea so chlorine combining with urea to form chlorourea is one possibility. Creatinine can also lead to some fairly persistent CC. Monochloramine would be another component of CC though that is the most easily eliminated. The UV in sunlight breaks down hypochlorous acid to hydroxyl radicals that may help to keep CC in check so that most low bather load residential pools have very low CC levels (<= 0.2 ppm usually; almost always <= 0.4 ppm).
The thing is that not all CC are bad. The test doesn't distinguish between the different types. Many municipal water districts use monochloramine at around 1 ppm, for example. It is presumed that at higher CC levels in pools there will be more of the "bad" CC such as nitrogen trichloride which is very irritating or trihalomethanes some of which are carcinogenic, but this doesn't take into account the active chlorine (hypochorous acid) level. In pools with CYA, there should be less nitrogen trichloride produced and ironically the CC level will be higher since everything gets oxidized more slowly by chlorine.
How high is the CC you are seeing? Are you using a FAS-DPD test kit for that determination? Does the water smell "bad" or does it have the faint smell of chlorine bleach or no smell at all?
I keep the cover on my pool almost all the time except when it is in use, but that is pretty much every day for 1-2 hours, longer on weekends. I almost always measure <= 0.2 ppm CC. The bather load is usually 1 person in 16,000 gallons and 2 people on the weekend. Even after a pool party with around 6 people in the pool, I still only measured <= 0.2 ppm CC the next day (it might have been <= 0.4 ppm CC shortly after their swim). Maybe your FC level is too low for your CYA level. Can you please tell us those water parameters?