Please read the following table in HTML format from a webpage and then answer the question in detail according to the table. Each table cell is defined by a <td> and a </td> tag. Each table row starts with a <tr> and ends with a </tr> tag. 'rowspan=m' and 'colspan=n' represents a cell spaning over 'm' rows and 'n' columns.

Webpage title:
Bluebell Records
Table title:
33 rpm
Table:
<table id='hittask' contenteditable='False'>
<tr> <th colspan=1 rowspan=1 > Catalog number </th><th colspan=1 rowspan=1 > Year </th><th colspan=1 rowspan=1 > Artist </th><th colspan=1 rowspan=1 > Title </th></tr>
<tr> <td colspan=1 rowspan=1 > BBLP 35 </td><td colspan=1 rowspan=1 > 1965 </td><td colspan=1 rowspan=1 > Bruno De Filippi e il suo complesso </td><td colspan=1 rowspan=1 > Live al Santa Tecla di Milano (1963) </td></tr>
<tr> <td colspan=1 rowspan=1 > BBLP 37 </td><td colspan=1 rowspan=1 > 1966 </td><td colspan=1 rowspan=1 > The New Dada </td><td colspan=1 rowspan=1 > I'll go crazy </td></tr>
<tr> <td colspan=1 rowspan=1 > BBLP 38 </td><td colspan=1 rowspan=1 > 1966 </td><td colspan=1 rowspan=1 > Carmen Villani </td><td colspan=1 rowspan=1 > Carmen </td></tr>
<tr> <td class="highlighted"  colspan=1 rowspan=1 > BBLP 39 </td><td colspan=1 rowspan=1 > 1967 </td><td class="highlighted"  colspan=1 rowspan=1 > Fabrizio De André </td><td class="highlighted"  colspan=1 rowspan=1 > Vol. 1° </td></tr>
<tr> <td colspan=1 rowspan=1 > BBLP 30 </td><td colspan=1 rowspan=1 > 1968 </td><td colspan=1 rowspan=1 > I Barritas </td><td colspan=1 rowspan=1 > La messa dei giovani </td></tr>
<tr> <td colspan=1 rowspan=1 > BBLP 31 </td><td colspan=1 rowspan=1 > 1968 </td><td colspan=1 rowspan=1 > Michele Lacerenza </td><td colspan=1 rowspan=1 > Never my love </td></tr>
<tr> <td class="highlighted"  colspan=1 rowspan=1 > BBLP 32 </td><td colspan=1 rowspan=1 > 1968 </td><td class="highlighted"  colspan=1 rowspan=1 > Fabrizio De André </td><td class="highlighted"  colspan=1 rowspan=1 > Tutti morimmo a stento </td></tr>
<tr> <td colspan=1 rowspan=1 > BBLP 33 </td><td colspan=1 rowspan=1 > 1968 </td><td colspan=1 rowspan=1 > Fabrizio De André </td><td colspan=1 rowspan=1 > Vol. 3° </td></tr>
</table>
Question:
What is strange about the numbering system used for the 33 rpm catalog?
Answer:
There is a chronological incongruence in the numbering of the 33 rpm catalog: after Fabrizio De André's Vol. 1° (BBLP 39) the numbering starts back from BBLP 30 which is the number for I Barritas' La messa dei giovani.