I force-downgraded samba 4.14.4 to 4.13.9 (itself released recently,
11th of May). It works as expected.
The cvs diff with respect to the current pkgsrc version is attached,
in case someone else hits the same problem. Surely the other packages
using samba should be also rebuilt - and database/ldb uninstalled, as
it conflicts with samba 4.13.9.
I basically just changed the package version in the Makefile, removing
references to database/ldb; edited the distinfo file and ran 'make
distinfo'. The PLIST was also manually adjusted.