In our tests, it works fine and we haven't received similar reports from the customers who are currently customizing AdsManager in these days.
In your case, the problem could be a conflict with other installed extensions or how you adding the new Ads. Additionally, we always recommend to download and install the latest versions to work with the most recent versions.
As part of our support service, we review the procedure and test the same case on your site with a hands-on approach. If it's necessary we access your site with an administrator or an FTP access that you provide to look further into the issue.