Until now all the tooltip description for Summoner Spells in-game only provides the original CD of the respective spells, regardless of the Masteries you have picked.

For example: you will see that the CD description of Teleport from its tooltip always appears as 300 seconds even you use Masteries (Spatial Accuracy and Presence of the Master) that reduce the CD. But this bug does not affect the actual CD nor the countdown.

I think that for consistency, the tooltip description should be update according to the Masteries just like how you treat a Champion's ability.