Good ask.
I find the current pair of HP and Temp HP bars to be vague and need guesswork to figure out which is which, and how much temp HP is left. This bit of UI needs enhancement, too.
Also, I don't think Aid provides the 5 hp healing when cast a second time?
there is a temporary hp bar? haven't noticed it yet.
Aid is a bit of an outlier. i had this discussion in my TT group, so i can understand, when it does heal 5hp on second cast, but i think you are right.
but +1 from me for a temporary hp bar.