Marc, I was able to put enough horizontal pressure on the closing strip with my thumbs and forefingers to move the strip back into the correct position. The sticky compound under the strip was flexible enough to allow this movement. I then cleaned off the excess compound. I will watch it for awhile and see if it moves again or if the sticky compound holds it in place.
If you are unable to slide your closing strip back into position in this manner, I would consider the very gentle application of a little heat with a heat gun or hair dryer to see if this might loosen it enough to allow movement. If this doesn't work, I would consider a little more mechanical force. Try holding a piece of hardwood (say 1/4 inch dowel with a square cut end) against the strip as a softener. Tap gently alternating between top, middle and bottom of the strip. You may need a helper to put a little downward pressure on the exposed end of the surround you are trying to cover. If this doesn't resolve the problem, I am out of suggestions. Perhaps others could chime in.