Parameters not being bound from Angular Http Post Body #4566

Hello, were having great difficulty getting the parameters to be successfully bound after submitting a post from the HttpClient in our project.

Our interceptor to handle the cookies and auth,

@Injectable()
export class AuthConn implements HttpInterceptor {

    private _cookieService;

    constructor(private cookieService: CookieService) {
        this._cookieService = cookieService;
    }

    intercept(req: HttpRequest<any>, next: HttpHandler): Observable<HttpEvent<any>> {

        if (this._cookieService.check('Abp.AuthToken')) {

            // We have our auth token..
            let bearerToken = this._cookieService.get('Abp.AuthToken');
            // Clone the request to add the new header.
            const authReq = req.clone({headers: req.headers.set('Authorization', 'bearer ' + bearerToken).set('Content-Type', 'application/x-www-form-urlencoded; charset=UTF-8')});
            // Pass on the cloned request instead of the original request.
            return next.handle(authReq);

        } else {
            // @todo This should sign the user out of the application...
            console.log('here');
        }

    }
}

Our endpoint request:

console.log(gridSettingsObject);

        // Finally go and update the server with our new item.
        this.http.post('http://localhost:22742/api/services/app/UserGridSetting/SaveUserGridSettings', {'jsonData': JSON.stringify(gridSettingsObject)}).subscribe((d: any) => {
            console.log(d);
        });

And finally our C# endpoint:

public async Task<int> SaveUserGridSettings(string jsonData)
        {
            var userId = AbpSession.GetUserId();
            var setting = await _repository.FirstOrDefaultAsync(s => s.UgsUserId == userId);

            if (setting == null)
            {
                setting = new UserGridSettingModel();
            }

            setting.UgsColSetting = jsonData;
            setting.UgsUserId = userId;
            setting.CreatorUserId = userId;
            setting.DeleterUserId = 0;

            return await _repository.InsertOrUpdateAndGetIdAsync(setting);

        }

jsonData just simply never makes it into the parameters but the endpoint is reachable. Whats even stranger is that when doing x-www-form-encoding or multipart in postman the parameter is found. Though changing the content type within our interceptor did not provide the same results so we are stuck..