Ok, a couple of things to look at here because you made new columns. The name of the column when using http requests has to match the internal/entitypropertyname of the column. These names are kind of encoded, but they use SharePoint's special encoding, not the usual encodeUrl.
You can see the name that will be used in the browser address bar when looking at the column settings. I made the same columns in a list and highlighted what is in the address bar.
New SharePoint Column Names
Also, you can send an HTTP request to the list using the endpoint "/fields" and it will get all columns/fields for the list and the properties of each. I'm putting an example below, and I specifically selected some properties to trim up the output. But you could just end it with /fields and get every property for each column/field.
_api/lists/getByTitle('@{variables('ListName')}')/fields?$select=
DefaultFormula,
DefaultValue,
Description,
EntityPropertyName,
Id,
InternalName,
Required,
StaticName,
Title,
FieldTypeKind,
TypeAsString
Below is an example of the get fields http GET request.
HTTP GET Fields selected properties
Below is the output when running the http GET fields.
HTTP GET Fields Output Results
So even though I named the columns "Line Manager Approval" and "Division Manager - Approval_Test" the names to use in the http request will be "Line_x0020_Manager_x0020_Approva" and "Division_x0020_Manager_x0020_x0" even though they seem incomplete.
Here is an example of the Patch when using the new column names.
Patch Step with New Columns
And the Outputs of the step look like this:
Patch New Columns Output
All of the above will help you get more specific info on what to put in the name of the field for the PATCH request, but it doesn't explain why you are getting duplicate results for those columns.
Could you run the HTTP GET request for the fields and then find the two columns in the output and see if there is anything that might be causing them to be the same. You could run the GET request without the selected properties and then then screen shot the results for each of the columns ManagerText and DivisionManager. Maybe we can see something within those column properties that is causing this issue?
