"__APPEND__" don't work in settings

[dimyy]

I try to modify Settings page (/#Admin/settings)
I modify
1. /custom/Espo/Custom/Resources/layouts/Settings/settings.json
2. /custom/Espo/Custom/Resources/metadata/entityDefs/Settings.json

In layouts I add
[ "__APPEND__", { "label": "SLA Default", "rows": [ [{"name": "slaUrgentDefault"}, {"name": "slaHighDefault"}], [{"name": "slaNormalDefault"}, {"name": "slaLowDefault"}] ] } ] Error in console: Uncaught TypeError: Cannot use 'in' operator to search for 'customLabel' in __APPEND__ If I try this construction without "__APPEND__" my description work but original layout lost.

[yuri]

It's not supposed to work here.