Yes, the thirtieth issues of Monomyth: this contrarily-named phenomenon relates to the 'zine's historical numbering confusion, which meant two nearly adjacent issues, each published in 2004 – volume 4.3 and volume 4.5 – both had claims to be the thirtieth released. The discrepancy depended on whether or not the two earlier Yearbooks counted towards this total, an unresolved conundrum that had arisen at the time Monomyth returned from a long hiatus in early 2003, since when the magazine's covers had borne a pair of competing numbering systems. The 'Issue' count incorporated the Yearbooks, while the 'Number' count disregarded them – this is not to mention the additional 'Volume' reckoning, introduced at the same juncture as those twin tallies, which designated issues altogether differently (e.g. 4.3 was the third release of 'Year 4' of publication) and was intended to cut through such confusion but in fact rather added to it temporarily.
Hence the decision was taken to publish five issues of Monomyth during 2004 rather than what would, at the time, have been the usual four (4.5 being the additional instalment), in order to celebrate both versions of the landmark within the same calendar year. 4.3 is "Issue 30", while 4.5 could be called "Number 30".
The serial Pentacle by DS Davidson was especially commissioned to run across all five releases as part of the extended celebrations, and the cover of the very first issue was reprinted as the cover of 4.3.