I have 6 ER-X in service and I've noticed twice now (once each with two different ones) a dialog box that pops up when you have the GUI open sitting at the dashboard. The dialog says
[address of router] says:
DataTables warning: (table id ='DataTables_Table_4'): Requested unknown parameter '0' from the data source row 1
I'm not sure if the exact text was the same the first time but I do remember the DataTables part.
While the dialog is open the Tx/Rx bar graphs stop refreshing, but if you click OK they suddenly spit out a bunch of readings (to catch up) and then everything continues working as usual.
I don't know if this is important but I thought I would mention it. Unfortunately I can't tell what causes it and have not been able to duplicate it. Usually it happens if I have left a GUI window open and forgotten about it for a few minutes.