Problems importing WMF files created in Mathtype in 16.3 on Windows machine.

I have a large suite of Technical publications to manage. Many of the files contain linked .wmf exported drawing files. Since the 16.3 update the fonts in those files has been replaced with whats shown in the attached screenshot. This is a major issue for me as we are talking about hundreds of images. What has cuased this and how can i fix it? i guess rolling back the version might work but thats not a decision i can make for my company at this stage. Your help appreciated.

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