There is more than Reverse Osmosis going on here. That UV light treatment "box" (the little black one) is not part of reverse osmosis, but is an additional disinfection step. These usually are replaced annually. Likewise on the carbon filter. That is pretty much a taste and odor filter. Likewise, replace annually or sooner...according to directions or flow amount.
The IRON filter is also NOT a standard RO filtration piece, but an add on as well. Replaceable.
What you have here is a complete water treatment system where someone has anticipated Bacterial, Iron, hardness (RO water is soft) and other chemicals like sulphur (bad taste/smell) or even Nitrates (RO).
Drain flow is CONSTANT WHILE MAKING WATER, but when the tank is full, drainage stops.
In fact, this may not be a Reverse Osmosis system at all, but just filtration which is completely different. RO sysytems sold at Home Depot (and others) generally consist of three separate "filter" piped in series, with drains. I don't see that here at all.
Regardless of what this system is, if it's putting out cloudy or smelly water, it's not working right and needs repaired.