Allegro Design Entry HDL (DEHDL) console window - my desired group is empty after exclude command

I've been using the command console and grouping items for many things recently and thought i had a grasp on it, however there is something i ran into that i don't understand.  I'll post the commands i used with comments on what i think is happening and where i don't understand.

GOAL: pre-select a box of component, wires and whatever else is inside, run a few console window command via a script and end up with a group that contains only the LOCATION properties of the components i selected that have such property.

====CONSOLE WINDOW======
set next a
find location (place all LOCATION properties on the page into GROUP A)
WARNING(SPCOCN-1200): Using group A
INFO(SPCOCN-1195): Group "A" contains: 0 bodies 19 properties 0 notes 0 wires 0 dots 0 images
find location (place all LOCATION properties on the page into GROUP B, this is currently just a copy of A, but will be turned into a "negative mask" to get what i want into GROUP A later)
WARNING(SPCOCN-1200): Using group B
INFO(SPCOCN-1195): Group "B" contains: 0 bodies 19 properties 0 notes 0 wires 0 dots 0 images
group c cxtgrp (using the mouse, i pre-selected an area of components [see image below] along with all the wires and power nets that were encapsulated, within this area are the LOCATION properties of the components i want to group together along with other various properties, nets, wires.. etc.   GROUP C now contains all these items)
WARNING(SPCOCN-1200): Using group C
INFO(SPCOCN-1195): Group "C" contains: 10 bodies 17 properties 0 notes 10 wires 4 dots 0 images
exclude b c (this turn GROUP B into a group of only LOCATION that contains all LOCATIONS on the page except the ones that were in my pre-selected area)
WARNING(SPCOCN-1203): Excluding from group B
INFO(SPCOCN-1195): Group "B" contains: 0 bodies 19 properties 0 notes 0 wires 0 dots 0 images
INFO(SPCOCN-1195): Group "B" contains: 0 bodies 14 properties 0 notes 0 wires 0 dots 0 images (this is what i expect, there where 5 components in my selection that had a LOCATION property and the properties difference before and after (19-14=5) is the result of excluding these 5 properties.  GROUP B is now a "negative mask" of the LOCATION properties i want)
WARNING(SPCOCN-1206): Not in this group (not sure what this implies or why it is here)
exclude a b (this should leave GROUP A with the 5 LOCATION properties i'm trying to group together.)
WARNING(SPCOCN-1203): Excluding from group A
INFO(SPCOCN-1195): Group "A" contains: 0 bodies 19 properties 0 notes 0 wires 0 dots 0 images
INFO(SPCOCN-1195): Group "A" contains: 0 bodies 5 properties 0 notes 0 wires 0 dots 0 images (This is the end result i expect where GROUP A contains the 5 LOCATION properties)
WARNING(SPCOCN-1196): Group "A" is empty. (This is the part i don't understand, i seemed to have had what i needed, but all of a sudden GROUP A is now empty????)

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I've also tried various other ways to obtain this GOAL all of which end in the same result.   Towards the end of my console commands i get an INFO message saying that GROUP A contains the 5 properties i desire, followed by a WARNING message that GROUP A is empty.  Why does GROUP A go empty?  There are no other commands that i ran between the INFO and WARMING messages.

Also, what does the "WARNING : Not in this group " message imply?