There was a related Bug #8554 (New printers are not added to the registry and because of this not shown in windows). This bug was fixed - except in the situations below. But I was told in the other bug report to open a new one.
The man page says for the parameter 'printer name':
printer name (S)
If specified in the [global] section, the printer name given
will be used for any printable service that does not have
its own printer name specified.
If you have a 'printer name' entry in the [global] section, and add a printer service which doesn't have this parameter (the situation where the entry from the global section should be used, according to the man page), then the printer is not shown in windows after a reload/restart.
If you have two printer services with different names in , but with the same 'printer name' parameter, the new printer is also not shown in windows after a reload/restart. We use this here since years to provide virtual printers with different settings (like one with black/white and one with color as default) to the users. But both of them are pointing by 'printer name' to the same printer in lprng.
A workaround is, like in the related bug, to run
# rpcclient -c "enumprinters"
After that, the printer is visible in Windows.
I only tested this on XP (don't have any newer Windows here).
Both worked fine for many years and stopped working in 3.6.0 until yet. 3.5.12 is the last version where new printers in this two situations automatically appear after an restart/reload.
Thank you for reporting.
Fixed by fixing related bug 8554.