Maintenance Mode / Scheduled Maintenance issue

Hello Everyone

We have a single node that when people try to put into maintenance mode or scheduled maintenance it doesn't work. IE they click Maintenance mode within Manage nodes or on the node it doesn't work. However when myself and others that are within the same user group we are  able to put the node into maintenance mode or schedule maintenance and other user groups either works or doesn't work.

we have tried moving node to another polling engine, Different browsers etc. At the moment the node is down due to work at site. 

Anyone experienced this before or have any ideas.  

Many Thanks