HTTP Interceptor error "HTTP failure during parcing" on Post request

I have an http interceptor for all of my api calls that catches errors and also catches items for local storage to download. All of my api calls except 1 return JSON. The 1 api call that does not is returning a string. I am getting a "failure to parse" error message with that api call from the interceptor even though my post request is requesting responseType to be text. I am connecting to a Spring backend that I cannot modify, so I need to fix this in Angular. Is there a way to have the interceptor check if the expected response type is text and not throw that error for the 1 call, but otherwise throw the error if the response type should be JSON?

api service:

refreshDetails():Observable<any>{
     return this.http.post('../app/refreshDetail', {responseType: 'text'})
}

http interceptor:

intercept(request: HttpRequest<any>, next: HttpHandler):Observable<HttpEvent<any>>{
     this.totalRequests ++
     this.loaderService.show()
     return next.handle(request)
        .pipe(
          timeout(30000),
            tap(
              event=> {
                if(instanceOf HttpResponse){
                  let contentDisposition = event.headers.get('content-disposition')
                  if(contentDisposition !== undefined && contentDisposition !== null){
                    let c = contentDisposition.split(':')
                    if(c[1]!== undefined && c[1] !== null){
                      let c1=c[1]].trim().split('=')
                      if(c1[1]!== undefined && c1[1] !== null){
                        let filename = c1[1].trim().replace(/['"]+/g,'').toString()
                        if(filename !== undefined && filename !== null){
                          localStorage.setItem("downloadFileName", filename)
                        }
                      }
                    }
                  }
                }
              },
            (error: HttpErrorResponse)=> {
               console.log(error)
             }
            ),
            catchError((error: HttpErrorResponse) => {
               return throwError(error)
            }),
            finalize(()=> {
              this.totalRequests --
              if(this.totalRequests === 0) {
                 this.loaderService.hide()
              }
            })
          )
     }