Elgato changed the Stream Deck API in version 6.6 of their software. This causes any Stream Deck Plus dial presses to no longer work in X-KeyPad 1.5.1. X-KeyPad 1.5.2 Beta 17 corrects this issue. If you want to run Stream Deck version 6.6 or higher install X-KeyPad 1.5.2 beta 17.

https://forums.x-plane.org/index.php?/forums/topic/290585-x-keypad-152-beta/&do=findComment&comment=2696068

Note: You must uninstall the older X-KeyPad Stream Deck plugin and then install the new per the release notes.