March 2019 Update: WIRIS has now announced a workaround for randomly resized equations. I don’t know for sure that that’s exactly the same problem as the shrinking formulas, but it could be. Definitely worth checking out if you’re experiencing this issue.

One teacher had an issue in MathType that involved saved formulas in a Word doc shrinking after editing and saving them again (even if the edit involved no actual changes).

The weird thing is that we tried with another user on the same machine with the same document and couldn’t replicate the behavior, so it seemed to be tied to the user profile, but then later, with a fresh user profile, the issue still seemed to persist. So maybe that was a weird anomaly (it not shrinking)?

I did a bit more digging and Googling and came across this answer from WIRIS:

This is an issue with Retina displays, so that’s one possible workaround: if you have a non-Retina display, use that when inserting or editing equations. The equations will be fine if merely viewed or printed when using a Retina display, but when you insert or edit one is when the sizing issue happens.

As Charles suggested in an earlier reply, “Consider reverting to Version 16.15.” This is, in fact, Microsoft’s recommendation as well. The answer on an earlier question in the Microsoft Community answers forum describes how to do that.

“[F]ine if merely viewed or printed” means, as far as I can tell, if you have already existing formulas that haven’t been edited.

We tried reverting to 16.15, and that seemed to fix the issue.

For Munki users trying to downgrade Word to address this particular MathType issue, this is what worked for us:

• Import Word 2016 (version 16.15).
• Get the installs array of the binary at /Applications/Microsoft Word/Contents/MacOS/Microsoft Word, and put that in the pkginfo.
• Modify the pkginfo to also change the version to be higher than 16.16. For us, 16.16.18091015 was sufficient for the change to take hold.
• Create a new catalog called mathtype, and make that the only catalog for this pkginfo.
• Put in a preinstall_script that checks for the existence of /Applications/Microsoft Word, and deletes it if necessary. If you don’t do this, Munki will install 16.15, but it won’t actually replace 16.16.
• Add the mathtype catalog to the relevant manifest(s) you want to have this downgraded version of Word. Put this catalog before production, testing, or any of the other regular catalogs you have (more details on why).

Example of the preinstall_script:

This downgrade procedure is modeled after the general approach to downgrading via Munki, outlined on the wiki.

P.S. The shrinking MathType formula problem persists in Word 16.17 (Word 2019).