It is bad practice to have two methods with names that differ only in capitalization. If a developer does not notice both methods they may call the wrong one. If they do notice then they will have to waste time investigating which method needs to be called.

Change the names of either one or both of the methods to make the distinction between them clear.

In this example the ConvertToIso method exists twice with two different capitalizations. One should be removed.

Robert C. Martin, Clean Code - A handbook of agile software craftsmanship, §17.N4. Prentice Hall, 2008.