How come open water is removed why doing basic SNAP pre-processing?

Hello all,

I’m learning basics of SAR pre-processing using SNAP and something I’ve noticed that in the final step where I convert Linear to dB, the open water is “removed” and I can’t get any pixel values when hovering the cursor. Only water bodies located on land are displayed. Any reason for this?

I’m doing a MSc thesis and am quite the beginner still. The data I’m using is Sentinel-1 GRD data.