New Label Format entries produce blank name badges

Not sure about cause and effect, but when I create a new Label Format of type 'Name Badge', and try to use it in a Badge Layout - the preview output is completely empty. I noticed that the newly created label format rows (option_value table) do not have the same format in the values column (name property seems to be missing) - and option_value.name is set to custom_1, custom_2 rather than the machine name version of the label title. Not sure if that's relevant to this problem or ??? (see attached).

This MAY be related to the fact that the name badge code is expected a known / fixed label format ? or ?? However the 'blank preview' bug also occurs if I COPY the original Avery 5395 label and then select the copy for my event name badge - so I'm pretty sure it's a 'linkage' issue.

I also get a bunch of notices when I save a new Label Format (see attached). These do not happen when editing / saving an existing label format.