.Net client issues when using refresh tokens

I am trying to use the .Net SDK, versions 6.2 and 6.14, with refresh tokens but am having issues. We create a DropboxClient with a DropboxClientConfig with the HttpClient configured with a short 7 second timeout and proxy configuration. This setup has worked well in all environments with long lived access tokens for years. When working with Refresh tokens, I am having the following issues:
1. API calls work fine when calling locally (where I don't need a proxy) and take less than a second
2. When deployed to our test environment, the API calls timeout after 100 seconds
In the refresh token case, I suspect that the Dropbox client is not honoring our DropboxClientConfig. I've examined your Dropbox client code and this indeed looks to be the case. When your code tries to retrieve a new access token using the Refresh token, it uses a default HttpClient (with 100 second timeout), not the one passed via DropboxClientConfig.

Please comment how to address this. I cannot meet the Sept 30th deadline if this code does not work.