Hi Tom.
This issue appears to be a change in DashBoard to send multiple RossTalk messages using the same connection for all tasks in a panel instead of in individual TCP/IP Connections for each one - this was changed in 8.4 to avoid overwhelming the device with too many connection requests and to guarantee the order of the messages.
It has recently been discovered that this change can cause the messages to hit a size limitation on the XPression's receiver side. An update to XPression will resolve the issue - adding pause messages every few (5 or so) tasks to wait a few hundred milliseconds would work around the issue.
James
#DashBoard