Calc: How to find anomalies

[clear]

By chance, I found two anomalies in my numerical data. Numbers prefixed with ticks, making them text.
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They became apparent when I used the autosum Sigma after clicking on the cell below the last data row. The range in the resulting formula did not reach to the top of the column. It stopped below the cells with the ticks.

Also, again by chance, I found ticks prefixing dates when I sorted on that column. Those I fixed with @newbie-02 regex solution from 2020:

How to get rid of the ' in front of a date?

hello @Silver77, just try this tip: There is a solution for this. It involves a “find and replace” function. From the “Edit” menu, choose “Find & Replace.” In the “Find” box, type “^.” (i.e., carat + period). In the “Replace” box, type “&” (without the quotes, of course). But you have to do one more thing for this to work. At the bottom of the “Find & Replace” window you’ll see a button that says “More Options.” Click on it, then select the box next to “Regular Expressions.” You shoul…

What other anomalies are common / might exist? and how can they be detected?

[mariosv]

How is the data obtained, by receiving the file as is, importing a CSV or another type of file?

[clear]

Lets suppose your first source, an ods I received.