Different ways of extending a class functionality esp. adding getProperty inconsistent

When getProperty is used e.g., to mimic a Map behaviour, the result differs depending on whether getProperty was defined directly in the class, added through a mixin, or through a metaclass.

===
class FooWorksAsMap { // class names the same length as LinkedHashMap to make output pretty
def getProperty(String foo)

}
class BarWorksAsMap {}
class BaxWorksAsMap {}
@Category(BarWorksAsMap) class C {
def getProperty(String foo)

}
BarWorksAsMap.mixin C
BaxWorksAsMap.metaClass.getProperty =

def maps = [new FooWorksAsMap(), new BarWorksAsMap(), new BaxWorksAsMap(),
[foo:'OK:LinkedHashMap.foo', class:'OK:LinkedHashMap.class']]
for (def prop in ['foo','class']) {
for (def m in maps) {
def op = "$

.$prop"
try

catch (t)

}
}
===