Thank you for your reply. Follow the Network Diagnostics for macOS instructions on Bug Reporting > Profiles and Logs to enable additional logging. I installed the profile described in this procedure and tried to obtain a log, but the problem could no longer be reproduced when the profile was installed. I deleted the profile and checked to see if the problem could be reproduced again, and confirmed that it could be reproduced in this case. the probability of this happening increases if the target app is the only app allowed on the "local network". Our research has confirmed that the issue becomes less likely to occur when the number of target apps increases, but it is also possible that installing a profile will make the issue less likely (or not) to occur.