Autoencoder train and test accuracy shooting to 99% on few epochs
The issue turned out to be MinMaxScaler. The issue was sorted after using standardization instead of normalization. (I am not sure as I did not completely verify but best possible guess as compressed output was mostly mapping one feature) One of the feature X had much higher values after normalization then the other features (probably due to outliers in other features). So the the feature X pretty much mostly contributed to the Accuracy.