Spells: Initiate Symbol of Brell Serilis strengthen effect only lasts 30 seconds

[Orxudan]

When I right click the Initiate Symbol of Brell Serilis for the Strengthen effect, I get a Strengthen buff icon that says duration is 27:00 when moused over. In my inventory screen, my strength raises by 10 points. After 30 seconds however, my strength returns to normal even though buff icon is still up and reads 26:30.

[Boomlaor]

I experience this as well.

Durkon