You need to say more about your problem and provide specific examples of the style, how the items were brought into Zotero, from which database(s), what you see , and what you want to see.
Records from PubMed will contain both the DOI and PMID. The PMID (and maybe the PMCID) will be in the Extra field in each record. [That is if the record has a DOI.] Zotero doesn't currently have a designated PMID field but the PMID in the Extra field can be included in the citation you enter when the style calls for it.
The PMID is cited in the "Extra" field. When I drag the citation to my Word document, the only thing that shows up is the DOI. This is a recent change, and I wonder if it is related to updated format in PubMed.
However, I just noticed that I can't find the format that we created for citations. I can't find it when I search the Preferences > Cite > Cite Additional Styles > +
This has moved beyond my comfort zone. Someone else will need to help. i don't know if the PMID is included in that CSL style.
However, please try adding the references using the add citation icon / dropdown instead of dragging. That isn't likely to solve your problem but it could possibly work.
You must've changed computer or somehow had a reset of some sorts and lost your custom citation styles. You'll need to get your hands on that .csl style again and install it.
Upgrade Storage
Records from PubMed will contain both the DOI and PMID. The PMID (and maybe the PMCID) will be in the Extra field in each record. [That is if the record has a DOI.] Zotero doesn't currently have a designated PMID field but the PMID in the Extra field can be included in the citation you enter when the style calls for it.
https://www.zotero.org/support/reporting_problems#reporting_zotero_problems
However, I just noticed that I can't find the format that we created for citations. I can't find it when I search the Preferences > Cite > Cite Additional Styles > +
The title we use is ActX Standard Style
However, please try adding the references using the add citation icon / dropdown instead of dragging. That isn't likely to solve your problem but it could possibly work.
You'll need to get your hands on that .csl style again and install it.