It May be a reagent problem. You can troubleshoot the purification by taking an aliquot of every binding and wash eluate from the column. Precipitate a sample of each using iso propanol and you should see which step is not behaving as it should and you can investigate the reagent concerned

It is possible that you have a small and invisible precipitate so dissolve the residue that you have and measure its OD260. Perhaps you simply do not have much plasmid

The cloudy phase that you observe upon adding isopropanol to precipitate the eluted DNA is due to microbubbles formed by degassing of the isopropanol when it is mixed with the aqueous elution buffer. As pointed out by Paul Rutland, pure DNA precipitates are transparent and difficult to see, and it would be worth while to check if you can recover some A260 material after washing with 70 % ethanol, drying briefly and trying to redissolve whatever sticks at the bottom of gthe centrifuge tube. Be careful not to loose the DNA pellet upon decanting the supernatant after centrifugation: don't pour it, but suck it carefully with a pipet, trying not to touch the side where the DNA pellet is supposed to lie.

As you said that the pellet was very less. that can be a valid reason but you can look at various other factors also. Sometimes the plasmid also gets transparent which is not visible to naked eyes so for that you can check the ratio of 260/280 to determine if DNA is present in the sample. Another thing you can do is check all the reagents and use a fresh column every time. The same issue happened with me also but when I checked the ratio it was 1.8 which confirmed that the DNA was present.

Thank you everyone for your thoughts, comments and suggestions on this ! I'll give it a try on the next prep to make sure the plasmid DNA is present. Most likely by measuring OD260/280 Since columns are practically new and I never re-use them