I believe what is happening is you already had galavnize (new term for adlo bubble) on the person. You then cast adloquium again but the first was stronger than the second and therefor did not apply a new bubble.
casting a lower healing adloquium will not renew the previous galvanize or replace the bubble.

eg.
First adloquium crit for 1000 putting a 2000 bubble on target
with 4 seconds remaining on this bubble you cast a normal adloquium hitting for 700 which is a pathetic little 700 bubble. The new 700 bubble will not replace the 2000 bubble.
Galvanize will remain on the target until one of 3 things happens.
1. 30 seconds time has passed
2. the total number of health points generated by the shield has been absorbed.
3. A larger Glavanize is cast replacing the original bubble and resetting the count down to 30.