The 'Crushing Wall' enchantment on Maelstrom Destruction Staves is currently bugged. When in a group with multiple other people also running Wall of Elements in conjunction with a maelstrom staff, only one person at a time will get the buff to their light attacks. It will be the first person to cast wall of elements that will be granted the crushing wall bonus to light/heavy attacks while everyone else will not get the buff until the first person's wall runs out, at which point another person will get the buff, but only one person at a time will have the bonus to their light/heavy attacks.
I've included a video of one of our tests in which you will see that, without wall down, my light attacks were hitting for 1114 and 1783 on non-crits and crits, respectively. With wall down and the crushing wall buff, my light attacks were hitting for 2154 and 3446 on non-crits and crits, respectively. Now when I applied wall before my buddy did, I gained the buff to my light attacks, while his light attacks did not gain the buff from his wall. When he applied wall first, he then got the buff to his light attacks while mine were still hitting the same values as if I never applied wall in the first place, it was only until his wall ran out when my light attacks started to get the buff. We have tested this with more people in a group and while using the different forms of wall (flame, frost, shock) and it made no difference. This bug affects all competitive raiding guilds and considering how hard and long most of us had to work for a maelstrom staff, it would be nice to see this fixed as soon as possible (along with Maw of Lorkhaj on console).
Link to video:
http://xboxclips.com/Colt Tanks/dac4d025-e6e1-4167-aac5-67ded572ac3e/embed