So I was playing as my lvl 40 rogue today using my level 20 Scorch while doing the 'Monkey Ball' quest. I noticed another user (rogue) summoned Scorch as well. As we played through the level I noticed that my shield was failing to work. I was trying to use it right after the other user's shield went down to keep a constant shield going. We tested it and indeed it seems as though when used in succession after another Scorch shield; Scorch's shield fails.
Has anyone else noticed this problem or am I late on an old issue?