Snapshots: Permanently deleted incorrectly

Scenario: 5 snapshots. I want to delete the first four. I highlight them, right click, and select delete.
Result: Numbers 1, 3, and 5 get deleted. I wanted and had not selected #5.

Scenario: 5 snapshots. I want to delete the first three. I highlight them, right click, and select delete.
Result: Numbers 1, 3, and 5 get deleted. I wanted and had not selected #4 and 5.

Scenario: 6 snapshots. I want to delete the first five. I highlight them, right click, and select delete.
Result: Numbers 1, 3, and 5 get deleted. #6 is still there but so are 2 and 4
Of the three that remain, I delete 2 and 4. Now only one - the new second one - remains