hmm. i don't understand the problem really.
if you define the same macro in two templates of the same level that are linked to same host, quite obviously the resolving of the macro is a bit undefined.

1. what do you mean by "the Macro's are global even they are defined only in templates" ?

2. how would you expect for this to behave ?

I have

HOST
– Template A
---- Macro CLUSTER = cA
---- Value of CLUSTER inside the Template == cA
– Template B
---- Macro CLUSTER = cB
---- Value of CLUSTER inside the Template == cA

you see the problem

I would expect a nearest wins behaviour

e.g.

HOST
– Template A
---- Macro CLUSTER = cA
---- Value of CLUSTER inside the Template == cA
– Template B
---- Macro CLUSTER = cB
---- Value of CLUSTER inside the Template == cB

or

HOST
– Macro CLUSTER = cA
– Template A
---- Value of CLUSTER inside the Template == cA
– Template B
---- Macro CLUSTER = cB
---- Value of CLUSTER inside the Template == cB
– Template C
---- Value of CLUSTER inside the Template == cA

so you mean both templates are linked to the host directly ?
if so, there is no way to determine "nearest" one

yes, both are linked to the same host,

but the items are in different templates

my expected behavior is also

HOST
– Template A
---- Macro CLUSTER = cA
---- Value of CLUSTER inside the Template == cA
– Template B
---- Macro CLUSTER = cB
---- Value of CLUSTER inside the Template == cB
– Template C
---- NO MACRO defined
---- Value of CLUSTER inside the Template == {$CLUSTER}

i don't fully understand your schematics, but i'll try describing the problem as i might have understood it

if two templates that contain the same macro are linked to single host on the same level, you expect items from each template to use macro value from the same template.

is that correct ?

if so, what happens in nested configuration, where normally lower level template would override values coming from a higher level template ?

That is my misunderstanding

I expect, that lower level template overwrites it's values, BUT only for them self and not for all others.

User macros resolving are described in our documentation. Feel free to reopen if macros are resolved in other way on your system.