I already update to SNAP 8 and get same error in GUI: incorrect data check
I can provide the 2 data products, I down load them from https://archive.eumetsat.int/
They are S3A_OL_2_WFR____20180412T015741_20180412T020041_20180412T035521_0179_030_060_2520_MAR_O_NR_002.SEN3
and
S3A_OL_2_WFR____20180412T015441_20180412T015741_20180412T035135_0179_030_060_2340_MAR_O_NR_002.SEN3