Why does sunflower oil turned to green after frying?

After frying foods, for example, chicken or cutlets(mix of meat and potato) with frying sunflower oil, the oil turns green/greenish, is this oil spoiled and bad? Shouldn't I use the rest of the oil bottle? (I mean oil that has not been used yet.) The following photos are of when the oil is cooled.

Thank you

Is this can be related to my problem?

Source: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC10048579/

That oil just looks dirty to me. I wouldn't re-use it, but I don't see any visual indication that there's anything wrong with it.

It is normal for oil to turn dark with use, and darkening is a sign that the oil is no longer reusable and should be thrown away or recycled.