I tried to reproduce this error by taking a screenshot and convert to CSV. Then I go to BigQuery and create a table from an uploaded CSV file with auto-detect schema. I think I got an expected result below.

Here are my suggestion:

1. The BigQuery preview table is not sorted as the original file. From the screenshot, it could be a different part of data in your file which is not just 44 rows from what we've seen. Try query data first and make sure it's correct.
2. You mentioned that you import from Excel file. Try converting it to CSV first, in case it is some formatting issue from Excel. I recommend using CSV as a source input file as it is easier to export from Excel.