Strange anomaly in Sentinel-1 image

In GRD product S1A_IW_GRDH_1SDV_20210131T154915_2a_S1B_FIN_T133.7z0210131T154940_036384_044523_2A33.zip there seems to be an anomaly: missing data in a block in VH band in the central swath and missing data in VV in near-range and central swath. I have seen a bit similar anomalies before but they have been associated with sea area and (possibly) beginning or end of a data take. This time it is in the middle of a data take and even in the middle of a scene. Could anybody have an idea why this anomaly is now in the middle of land area ?

HI Yrjö, perhaps @peter.meadows has an idea. It does not look like RFI to me.

Hi, you are quite right, it is not RFI. The problem is related to missing data in either one polarisation (green block) or both polarisations (black block). You can check each polarisation separately to see exactly what data is missing in each polarisation. It is not possible to recover the missing data blocks.

This problem only occurs occasionally and is related to data downloading from the satellite - the ESA N-Cyclic reports include plots of the number of data gaps as a function of time (Section 6.1 - Level 0 Products).

This product is in the latitude zone where the footprint of the Spitzbergen receiving station is marginal, likewise the receiving station towards south. Very often a whole scene remains missing between the footprints. Now it seems that only few data packets remained missing in this particular scene.