1294 doesn't include retired devices (expected)
click filter thing
1306 which includes retired devices (unexpected)
Inventory view and group editor have different number of devices
Release : 21.2
Component : Performance Management Groups
The way inventory works is that it not only adds the group and its subgroup it also deduplicates items between the groups. So if an item is in the parent group and both sub groups it will only count it as 1 item.
Inventory is the group and it subgroups with a distinct filter to deduplicate if the item is in the group and a sub group(s). In the group editor view its only the items in that group it self. This is why you see the discrepancies between the group editor and inventory view.