Sorry, to clarify, the spotting of a single trigger word is not actually an intended feature of OpenEars or described as a goal here or in its documentation – this would use a newer part of the Sphinx project which hasn’t been implemented in OpenEars. It does get used that way and I try to help with this situation when it comes up, but Rejecto was designed with the intention to reject OOV for vocabularies with multiple words. Pocketsphinx uses its own keyword spotting API so it isn’t an unexpected result that the outcomes are different. This may be a case in which you’d prefer to simply use Pocketsphinx built for an iOS target, which is supported by that project to the best of my knowledge.
Regardless, I’m happy to continue to try to help you get better results. It isn’t clear to me from your response whether you took my first requested step of not using Rejecto while troubleshooting the VAD. It isn’t an expected result that a word found in your vocabulary that is significantly louder than the background isn’t heard at any VAD setting when Rejecto isn’t on. Is it possible that you’re using a different acoustic model with the pi version?