(Mis)Understanding ** matching

[cyb3rz3us]

The patterns help webpage says that ** can be used to match zero or more directory levels. However, I observe what apperas to be inconsistent behavior depending on how an include pattern is entered.

Let's start with the following path structure

/Volumes/borgLab/cyb3rzeus
└── Gtest 
    └── borgie4
	└── sub4a
	└── sub4b

If I use the following patterns, Gtest and its content are INcluded:

R /Volumes/hubble_data1/cyb3rzeus
+ **/Gtest
! **/Gtest

But if I use these patterns, all of Gtest is EXcluded:

R /Volumes/hubble_data1/cyb3rzeus
+ **/borgie4
! **/Gtest

The way I read the docs, my expectation was that Gtest should be included with both pattern sets so my question is why does ** seem match all pre Gtest directories with the first set of patterns but not match all pre borgie4 directories with the second?