Hi Jules,
Already working on a fix for this and will try to remember to loop you in once the fix is testable.
There's a couple of workarounds that might be useful to you in the meantime though. As you've already found, it's related to input sbet duration, and not necessarily what scan data is included so if you can reduce the duration of the input sbet it can bypass the error. It all depends on the layout and specifics of your project though. Lets say you have a 5 hour collection, but it's two suburban areas with a single road connecting between them. You can process the first half of the project and all of those runs, then the second half of the project and all of those runs and each will be aligned and contain the benefits of LidarQC, but then traditional registration would need to be used in the areas where the two sections overlap. In this hypothetical scenerio, it could be just the one road connecting the two suburbs that would need Run to Run registration on it.