The pin assignments for portBackbone, portSensorsA, and portSensorsB are incorrect and should be swapped. (https://github.com/AEAEmbedded/ESE_PROG/blob/00bf95ebf25179a4315e0e8f3ea09df347bc89fe/Code/WireScanner/examples/basic_wirescanner/basic_wirescanner.ino#L14C1-L16C41)
the correct code is
TwiPinPair portBackbone(W0_SDA, W0_SCL);
TwiPinPair portSensorsA(W1_SDA, W1_SCL);
TwiPinPair portSensorsB(W2_SDA, W2_SCL);