OK, I was able to reproduce this problem on my sole desktop system. One interesting thing I notice is that the requires: for this job are unique: it's the ONLY instance in all checkbox jobs where a requirement is expressed as "<something> not in [list]". So there may be some weirdness in the requirements evaluator that causes this particular scenario to fail. Now, to put a few wires in resource_info to measure what happens in this case...
OK, I was able to reproduce this problem on my sole desktop system. One interesting thing I notice is that the requires: for this job are unique: it's the ONLY instance in all checkbox jobs where a requirement is expressed as "<something> not in [list]". So there may be some weirdness in the requirements evaluator that causes this particular scenario to fail. Now, to put a few wires in resource_info to measure what happens in this case...