yep, tested in 8.4 2018-07-26 with no hals, single contract with 3 lines. The contract was never unOKed. Only the first line gets invoiced, all other lines are never invoiced. Will try to report a bug.
I would like to know what BackgroundHALShouldPause does, and how to use it. While it's listed in the HAL Primitives report, it is not used in source code and it doesn't appear in the LMS HAL...