You probably don't want to use the AFEventFrameSearch class. That class is handy to help you find event frames based on some common information, such as template name or referenced element name. Since you already have the Guid identifying the event frames of interest, you really don't need AFEventFrameSearch.
I'm surprised LoadEventFrames does not work, though I am confused about the usually return an empty list versus sometimes goes back 2 weeks. What version of AF are you using? I would think it should either return an empty list all the time, so I am curious as to why it sometimes does the 2 weeks thing.
You should be able to load one EF at a time with AFEventFrame.FindEventFrame. However, if you have more than a handful of EF's to fetch, this would be slow.
Your surprise was justified: The event frame guid's were a mix from two PI systems; our production system and our test system! So we need to update our mapping, our bad! It clarifies why we got random results.
Thanks for your reply!
Glad you figured it out and got it working. If you have further questions, you know where to find us.