Is this Webaccess or Workspaces as I noticed this problem in workspaces that they fixed in 2017.3.
P6621 Workspaces becomes unresponsive after repeatedly loading Service Catalog
Thanks for the quick reply Julian.
It's happening in Webaccess for us. We haven't got users onto Workspaces yet but having checked our test environment for Workspaces, it seems to be replicating the issue that occurs in Webaccess
Sounds like it is worth opening a support case for this one then.