To replicate:
With LLS:KIMBALLCOM61MT in your library (I suggest prioritizing it to the top for this exercise), consecutively run Passage Guides on the following overlapping passages and attend to the passages returned from this commentary:
1. Mt 18:21-22
2. Mt 18:21-23
3. Mt 18:21-24
4. Mt 18:21-34
5. Mt 18:21-35
6. Mt 18:12-19:1
7. Mt 18:12-19:29
8. Mt 18:12-19:30
My results are that the reference given for the resource is:
1. Mt 18:12-22
2. Mt 18:12-35
3. Mt 18:12-35
4. Mt 18:12-35
5. Mt 18:23-35
6. Mt 18:23-35
7. Mt 18:23-35
8. Mt 18:12-19:30
The weird results are 5., and 6., and 7.
This commentary has three relevant internal divisions: Mt 18:12-22, Mt 18:23-35, and Mt 19:1-30.
Since 1. falls entirely within the first range, I expect the first range to be the (only) range shown, and so it is (Mt 18:12-22). 
Since 2., 3., 4., and 5. overlap the first two ranges, I expect both ranges to be shown (Mt 18:12-35), but this only occurs for 2., 3., and 4. 5. neglects the first two verses of the queried passage. 
6. and 7. contain the entirety of the first two ranges as well as the part of the third, but the PG brings me only the second range (Mt 18:23-35).
Happily, 8., which simply is all three ranges, returns all three ranges (Mt 18:12-19:30).
Dear Faithlife: If this behaviour is a BUG, please fix it. If this is not a BUG, please reclassify it as a bug, and then fix it. Thank you.
Rationale: The passage put into the Passage Guide is the passage that the user wants to study. Therefore, ignoring commentary on parts of that passage simply because of how a commentary is internally divided is counter-productive. How problematic it is is especially apparent in this commentary, because the author (St. Thomas Aquinas) basically addresses each individual phrase in order.
