Hi @fedoras,
Actually, the leading zero behavior for the formatted catalog number was changed in v7.10.2, and after this request was made, we met as a team and recognized the need to have this be a configurable option.
So if you are using v7.9.6.2, the leading zeros should not appear, but in v7.10.2 or later, the leading zeros would appear after the prefix.
We are working on a change so that you can choose either to include leading zeroes or exclude them (as you intended in the NHMD896415 example), see #7080, stated for a new release in the next few months (v7.11.2).