upgrading herald of thunder shows wrong stats

hello,

i'm trying to upgrade my "herald of thunder" spirit gem, and instead of showing the current stats with changes highlighted, it shows the old stats as being zero. this is a minor bug, but it looks easy to miss.

note that i first got "herald of thunder" with a level 4 gem, and noticed this issue when i tried to upgrade to a level 6 gem. now that i'm trying to upgrade to a level 7 gem, i see the bug again, so it's not just a problem with the level 6 gem.

thanks.
-az