Multiple Volume Groups with the same name were not handled consistently.
Warnings about the duplicate VGs were not printed when lvmetad was used.
The VG name specified by a command would not always translate to the intended VG.
LVM always checks if the VG name specified by a command refers to more than one actual VG.
Copied from lvm(8):
When VGs with the same name exist, commands operating on all VGs will
include all of the VGs with the same name. If the ambiguous VG name is
specified on the command line, the command will produce an error. The
error states that multiple VGs exist with the specified name. To
process one of the VGs specifically, the --select option should be used
with the UUID of the intended VG: '--select vg_uuid=<uuid>'.