The numbers on my citations are in desending order
This morning a installed firefox 13, zotero 3.0.7 and the word for windows 3.1.7 add-in. I started a new document, picked a citation style and started typing. Each time I add a citation that citation becomes #1 and the previous citations take on a new number so they are in an inverse order. I switched to a different citation style and that did not help.
http://www.the-aps.org/mm/Publications/Preparing-Your-Manuscript#references
"Reference lists should be arranged alphabetically by author and numbered serially. The reference number should be placed in parentheses at the appropriate place in the text."
The APS style guide says this: This conflicts with the example that they give, but the Zotero style follows the stated rule, so as far as I can tell this is correct.
See e.g. Cell Physiology:
http://ajpcell.physiology.org/content/298/1/C38.full.pdf
the first three citations in this article are 1,8,20 (and that it starts with 1 is pure coincidence). This is the style currently required by APS journals. I think it's stupid, you may think so, too, but it's what they want so it's what Zotero is going to produce.
It's very well possible that this was fixed and some point in the past and we didn't use to do this correctly.
(As an aside on a separate issue, testing with the style turned up a small bug in the processor that could cause in-text citation numbers to fail to update (i.e. not the behavior you are describing, which does not seem to be a bug). I'm not sure whether this small bug would affect current Zotero, but you can check by refreshing the document. If citation numbers are corrected by the refresh, you'll want to be sure to refresh before finalizing a document. The bug has now been fixed, and the new processor version will appear in a future Zotero release.)