Game Review Confused

Two images: the first one shows the move played to be an error. The second responds to an effort to find a better move by saying the move actually played was best.

depth 18 vs depth 20? idk

It seems to me that the differences are more than apparent at depth 8. Bg7 is an error as it loses two queenside pawns. Qe7+ and Qb6 preserve them.

but, please pay for the site and its great knowledge!

What depth was Game Review ran on? 

Seem to be 18 and 20. Info in the image.

That's the Analysis tab. The Review process that runs on the site servers, is whatever you have set in your settings. For example, I default mine to depth of 26.

That said, even at similar depths, the review uses a different engine than what you have running for the analysis tab, so even at the same depth, there will likely be some differences there.

I use the default. Whatever that is. When I want to do serous analysis, I do it in ChessBase. Stockfish does better on my computer than on the website and doesn’t offer coach’s weird takes. Just raw data unfiltered.

Also my ChessBase account gives me access to the cloud.

If you haven't changed anything, I think default may be depth 18 on the sever analysis for review. If you don't mind waiting a bit longer, you'll probably get better results by bumping it to 26.

After recent update the quality of analysis has deteriorated

the quality of the analysis has recently deteriorated. Normal moves get brilliant and inaccuracies become blunders

Likely caused by the depth of the engine