Fail-to-wire Firepower 4K: Does LACP work?

I've seen conflicting reports that suggest that LACP might not work on an inline set on FP 4K. The topology is fairly straightforward: FP sits in between two devices that are connected by a port channel. Does this actually work with inline sets / IPS-only mode (e.g. "transparent" IPS)? Are there any caveats?