@EzraZebra this is another great question.
The trends page performs its search in an entirely key neutral manner. Searching in a given key transposes the chords of all the songs to that key regardless of the key that they were analyzed in.
We have the ability to transpose the midi of the song to whatever key the search is in but obviously lack the ability to do the same for the youtube video.
When you browse for songs in the TheoryTab database outside of trends it shows them in the correct key that they were originally analyzed in.
Hope that clears things up.
Dave.