.Net Core blocked by CORS policy error only when uploading a file

Is there something different that needs to be done when uploading a file? Every other call (Axios/Vue put) works fine except where a file is getting uploaded. It's going from example.com to api.example.com. Everything works fine locally hitting different ports.

ConfigureServices:

services.AddCors(o => o.AddPolicy("CorsPolicy", builder =>
            {
                builder.AllowAnyOrigin()
                       .AllowAnyMethod()
                       .AllowAnyHeader()
                       .SetIsOriginAllowedToAllowWildcardSubdomains();
                       //.WithOrigins("http://*.example.com"); //tried adding, nothing works when it's here
            }));

Configure:

app.UseCors("CorsPolicy");

And the controller:

[ApiController]
[EnableCors("CorsPolicy")]  
public class MyController : ControllerBase {
Public Model Put([FromForm] ICollection<IFormFile> files, [FromForm] string jsonString)

The browser output:

Access to XMLHttpRequest at 'http://api.example.com/api/YourKnowledge' from origin 'http://example.com' has been blocked by CORS policy: No 'Access-Control-Allow-Origin' header is present on the requested resource.

Request URL: http://api.example.com/api/YourKnowledge
Referrer Policy: strict-origin-when-cross-origin
Date: Sat, 03 Oct 2020 19:58:42 GMT
Server: Microsoft-IIS/10.0
Transfer-Encoding: chunked
X-Powered-By: ASP.NET
Accept: application/json, text/plain, */*
Accept-Encoding: gzip, deflate
Accept-Language: en-US,en;q=0.9
Connection: keep-alive
Content-Length: 10219
Content-Type: multipart/form-data; boundary=----WebKitFormBoundaryvIG7idij6Og7BH8r
Host: api.example.com
Origin: http://example.com
Referer: http://example.com/
User-Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/85.0.4183.121 Safari/537.36
files: (binary)
jsonString:{} 

Last note, I did find this Asp.Net Core API CORS policy error only in file upload, but I won't have just images uploaded. Did try setting it to test, but it didn't make a difference.