"Official" journal abbreviation of MAGMA I am struck by the use of "Magn Reson Mater Phy" as an abbreviation by the journal "Magnetic Resonance Materials in Physics, Biology and Medicine" (a.k.a. "MAGMA"). See here for an example.

Their instructions for authors say:


  In order to have all citations to the journal taken into account in
  the calculation of the Thomson-ISI impact factor and citation index,
  please always refer to MAGMA as Magn Reson Mater Phy in all your
  publications. Magn Reson Mater Phy is the only official abbreviation
  of the journal.


That use is of course reflected in the Web of Science.

On the same site, they say:


  Always use the standard abbreviation of a journal’s name according to
  the ISSN List of Title Word Abbreviations, see ISSN.org LTWA.


Using the LTWA and ISO-4 rules, I determine "Magn Reson Mater Phys Biol Med" as an abbreviation; note "Biol Med" and the extra "s" in "Phys". "Physics = Phys." is even an explicit example in ISO-4 (section 3.5) and often used, for example, in the abbreviation of "Medical Physics" ("Med Phys").

So, I wonder why Springer says the "official abbreviation" is one that is different from the LTWA. Is that for historical reasons, and MAGMA just sticks to it because the ISI impact factor is so powerful? Is there a title history that I may have overlooked? Or is there another reason Springer uses a different abbreviation for "Physics" and omits everything after the comma? In the whole ISO-4, I have not found any indication to do anything like that.

Update:
A little bit of history. MAGMA was born as "MAGMA" in 1993 (with no explanation of the meaning in the first editorial). The NML catalog says that "Issues for Apr. 1994- have subtitle: Magnetic resonance materials in physics, biology, and medicine." So there is no indication of any title not involving "Biology and Medicine".

The header line read MAGMA in all papers until the end of 1997 (see that year's last paper), and had been changed to "Magnetic Resonance Materials in Physics, Biology and Medicine" in the first editorial after the publisher had changed to Elsevier in 1998. It remained like this until issue 15 (some time in 2002), when the publisher changed to Springer; they started using "MAGMA" again until issue 18; since issue 19, they have been using "Magn Reson Mater Phy" in the header line until today. Note that the ISO-4 standard has not changed since 1997.

Also, the Web of Science says in the JCR:


  Titles 
  
  ISO: Magn. Reson. Mat. Phys. Biol. Med. 
  
  JCR Abbrev: MAGN RESON MATER PHY


So there is no doubt the abbreviation I determined is correct. (Yes, there is! Note the difference in "Mater" [my abbreviation, according to LTWA] vs. "Mat" [ISO abbreviation according to JCR].) But still my questions remain: 


Why does Springer/JCR use a different abbreviation? 
Who was the first to use it? 
And why do they still recommend using it?


And a bonus one:


Why does the JCR use a wrong ISO abbreviation?


Update: More facts.


MAGMA appears in the JCR for the first time in 1998, already as "MAGN RESON MATER PHY"
A fact that I have ignored so far is how the journal uses it's own name in references of their papers. Late 1997, MAGMA was cited "MAGMA", but I can't find self-citation after that (and before the JCR). So did the JCR ultimately define that abbreviation?
There is probably nobody but the particular administrators of the various organizations involved who can speak to the exact details of why this journal's abbreviations are inconsistent.

I suspect, however, that the answer that you would get, if you could track them down would be something along the lines of:


  I don't think it's inconsistent... hmm, I guess maybe it is?  We should probably try to figure out how to get that sorted out at some point.


The point is that curation is hard, curation of periodicals is harder, and curation of periodicals over long time frames and across multiple organizations is particularly difficult and easy to get wrong.  Worse yet, repairing a problem will often create more problems for the future (e.g., an inconsistency might get fixed by hard-coding in an alias).

Even within a single organization, it's difficult to handle different parts of a process consistently: for instance, yesterday I proofed my final version of a paper for a major journal and found that some of the links to instructions that the production staff supplied were incorrect.

All of this is a long way of saying: probably it's just an unintentional mess.  You can point it out to the people involved, and they might be able to fix it; they might also have work-arounds in place already and not care.  At the end of the day, however, it need not be your problem, unless you are in charge of curation of the journal or other resources involved.