Hi, we have identified the PPPoE issue and it was introduced in 15.1.3 while fixing a different problem. We have a fix and it will be in 15.1.4 which I expect will be availble in the next couple of weeks. If you are interested in a beta test load, let me know.
The issue is when leaving the Service Name or Access Concentrator fields blank. If you fill those in to match what is on the server, the problem should not arise. However, we realize that can be a standard config to leave those blank and accept what the server offers.
Thank you for reporting the issue and we apologize for the inconvenience.