Probably invalid code signing identifier

I sign my apps prior to shipping as part of a script which invokes the `codesign` command-line tool recursively as needed. For the last few months, my script's output contains this warning from the `codesign` tool:


***WARNING*** Probably invalid code signing identifier
com.mycompany.MyAgent-20181212-155237
for component 
/Users/jk/Builds/Release/Temp/MyApp.app/
Contents/Library/LoginItems/MyAgent.app
*** This may cause a "nested code is modified or invalid" error


and a similar warning for the executable within MyAgent.app.


I realize that my code signing identifier is probably longer than yours, but I do this because of the way that macOS stashes Login Items installed by SMLoginItemEnable(). By appending a timestamp to its bundle identifier during building and doing some Info.plist tricks, I'm always confident that MyApp is using the coincidently-built build of MyAgent. This long bundle identifier is of course then used as the code signing identifier.


The "may cause" in the warning in fact turns out to be "not". I do not get any "nested code is modified or invalid" errors. The code signature of MyApp verifies. MyApp and MyAgent run fine on my computer, and on users' computers.


Is there indeed something wrong with my code signing identifier, or is this warning a bug which I should report to Apple?