When attempting to update properties of a file, I get a "read only" error in one flow but not another for the same field.

[Anonymous]

For the two flows below, they operate in the same way except the first and (functioning) flow loops through all the files in the library and updates the field, whereas the second (non-functioning) flow only operates on a selected file. 

In both flows I check the file out, before making the property update however in the second flow I get the following error:
"The 'inputs.parameters' of workflow operation 'Update_file_properties' of type 'OpenApiConnection' is not valid. Error details: The API operation does not allow writing a value for parameter 'item/Locations[0]/Value'. This parameter is read only."

This is the functioning Flow, that updates the area field without issue:

This is the non-functioning flow that fails when attempting to update the area field. 

[Jronash]

Are both of these flows working on the same document library? Are they both using the same SharePoint connection? If they are in different libraries, does the flow have the same permission level in both libraries?

[Anonymous]

Both are operating on the same document library and same files. I am running them from the same account with the same connections. 

Also on the one that fails, if I manually enter array data then it updates without a problem, its only when using the dynamic content does this error happen, and only on this flow.

[Jronash]

I'm afraid I'm not sure what's going wrong. The next thing I'd do if it were my flow would be to take a closer look at the data that's being used in the flow that fails.

If you want to see more details about what's going on in your flow, go to the Run History page (you can get there by clicking 'All runs' on the main page for your flow).  At the top of the Run History page is a button to get a .CSV file.  If you download this CSV file and open it in Excel, it will give you detailed information about every action in your flow.  You can see exactly what the inputs were, and the outputs.

I'd start by doing two runs of your flow.  One with the manual data that succeeds, then a second run with the dynamic data that fails.  Then download your CSV and find the appropriate input/output columns and compare them.  Look for anything that's different, and it may give you a clue as to what's going wrong.