List ctrl will be updated when setting total lines count, before set custom data "msg", thus you won't get correct data.
A possible solution is to add action refresh after set custom data "msg", to force triggering "condition:on visible lines" again for all visible lines.
I had updated rex_listCtrl and rex_gridCtrl, now it will not update immediately when when setting total lines/cells count. Please download them again.
And here is a modified capx from yours, which could push 1 new line in front of list. It might fit your requirement, to show the latest data at the top of list.