I recently made a level 46 (ebon) cuirass (with and improved it up to "blue" level, then created a "blue" magicka glyph with a Pora potency rune (level 40-50) to enchant it. However, when I went to enchant, the the glyph doesn't show up as available to use on that item. I had to make and use a magicka glyph with Jaera (average) for potency instead.
I guess I don't get the distinction between the overlapping potency runes (ie Jaera works from level 35-45, and Pora from 40-50), especially since Pora doesn't seem to work for a level 46 item, so I had to go with potency runes that were "below" level 46.
What am I doing wrong?