Rings of light in cataract surgery

Even some people with their natural lens have issues with halos for various reasons, and the reasons vary with IOLs as well. Most people who see halos after cataract surgery don't find them to be  a real problem even if they don't go away. Usually studies on IOLs only ask about issues with halos at the 3 or 6 month point since many people have them initially but see them fade either after  the initial healing process or when their brain learns to tune them out, though some may see them take longer to be tuned out, a few years, or never go away entirely.

I'm assuming this was the standard monofocal IOL you got rather than a premium IOL like a multifocal? The reasons for halos vary, e.g. for a multifocal IOL there can be halos due to the light from the other focal point(s) being out of focus and at night without more ambient light the brain takes time to learn to tune it out. Diffractive multifocals, and the extended depth of focus Symfony IOL can also get a a different sort of halo, concentric rings from scattering off the IOL.

re: "own lense has flexibility where the artificial lense has none"

Actually some lenses are designed to accommodate the way the natural lens does, like the Crystalens, but they don't give much of a range of vision yet. Ones with a larger range of vision are still under development, though some are in clinical trials. There are other IOls designed to give a larger range of vision without the need to flex, multifocals or extended depth of focus IOLs like the Symfony. Currently more people opt to get those than the Crystalens, the pros vs. cons for those options tend to work out better for most people, but people's needs vary.

Aside from the IOL, I should have mentioned that dry eye can cause halos. Dry eye can be a temporary side effect of surgery, which some people don't notice because the issue is nerves having been cut which tell the brain the eye is dry and it takes some weeks/months  for the nerves to heal.   Even those who don't have IOLs, but who wear contacts or glasses, can have halo issues. They moderate links so google to find this, but to keep things in perspective,  one article mentions:

"The study, titled Needs, Symptoms, Incidence, Global Eye Health Trends (NSIGHT), surveyed 3,800 spectacle and contact lens-corrected subjects, 15 to 65 years of age, from seven countries (China, Korea, Japan, France, Italy, United Kingdom and the U.S.) to better understand the eye-related symptoms that vision-corrected patients experience. The NSIGHT data provided valuable information on how often patients experience halos and glare and the degree to which they found them bothersome. 

About half of the spectacle and contact lens wearers surveyed reported suffering from the symptoms of halos (52 per cent and 56 per cent, respectively) and glare (47 per cent and 50 per cent, respectively) more than three times a week. More than four of five patients who experienced these symptoms found them bothersome (84 per cent and 89 per cent for halo and glare, respectively). " 

You don't mention what kind of lenses you are wearing and how many rings of light you are seeing. So, it is hard for me to judge the reason for what you are seeing.

Many people like me, who are using Symfony lens, see about ten circles at night around lights. Those are due to the basic design characteristics of the Symfony lense. Other lenses or natural lens do not cause such multiple circles.

Many people see reflection from a light caused by the edge of the lens due to dilation of eye at night. That is not  the same as seeing multiple circles. The reflection from the edge is probably what your optician was referring to. However, that is a completely different visual effect from the multiple circles seen with the Symfony lens.