[Product Question] SkinCeuticals claims that oxidized Vitamin C is still effective. Is this true?

I've been using vitamin C serums from Geek & Gorgeous and Timeless for several years, and both have always arrived completely clear. I store them in the refrigerator, and each bottle lasts me close to five months.

Recently, I purchased a TNS "dupe" from Skincare Generics and noticed they also offered a SkinCeuticals-dupe vitamin C serum, so I decided to try it. The serum arrived already oxidized.

I contacted SG to request either a replacement or a refund. In response, they linked me to this SkinCeutical's article, which claims that oxidized vitamin C serum remains effective due to their special formulation.

This is the first time I've come across this claim. I've searched for discussions on the topic but haven't found much on this sub that supports it. Most dermatologists I've seen on YouTube seem to say the opposite, that oxidation indicates the vitamin C is degrading and becoming less effective.

I'm not sure what to believe. Any thoughts or insight on this?