BUG: add new column modifies content of other columns.

[benjamin_sasin]

I'm experiencing a strang bug, which could have been quite damaging to business here if I hadn't spotted the errors.

In the screenshots below, I am switching from the penultimate step in my ETL (first picture) to the last step (second picture).

The two steps are simply adding text columns and do not have any formula or relation to other columns at all

Yet in the last step (second picture) the data in columns application_state, students status, default_contact_status and--only in row 11--applied_program are overwritten with completely different data!

Is there any help please?

[az38 · Accepted solution]

Hi @benjamin_sasin 

please, pay attention to the preview date (right-bottom corner of your pics) - it's completely different

so, you should understand that in Power Query Editor mode is only preview of your data.

do not hesitate to give a kudo to useful posts and mark solutions as solution

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[benjamin_sasin]

Errr.. Why is the preview not the same for both steps of the ETL recipe? I am aware the preview of the query can be outdated, but I was assuming that the preview date would be the same for all steps.

Now I am trying to reproduce the situation and the preview is the same for all steps of the recipe.

Anyway, thank you for finding that out. I learned something.