Evaluation goes from -2.2 to -3.5 . Move isn't marked as inaccuracy/mistake/blunder in analysis.

This seems strange:



16. Ng3 is not marked as an inaccuracy or mistake or blunder even though it allows an obvious fork and makes the evaluation go from -2.2 to -3.5

The marks come from the automatic analysis and there the evaluation doesn't change that much, only by -0.2. This automatic analysis is just a quick blunder check and shouldn't be taken too seriously. If you really want to analyse a game or a certain position you should do it by yourself and let the engine calculate for 1-2 minutes per move at least (depending on your CPU, settings, etc.).