I will get on this now and let you know once I have finished. 
I don't think meta descriptions are being deleted. I believe too many pages are being created without them being added in the first place.
Of course, I could be wrong - Isaac knows best. 
But I am assuming that based on the pages that have the missing meta.  

Chris - 0.01% chances they got deleted. 99.99 chance they were created without them.

Isaac ,
Thanks for confirming what I believed to be the case. As I stated above, these pages are being created without any meta added. 
I am adding them now. 

Chris , so far I have added meta, site titles and keywords to the following pages.
I will continue with the rest tomorrow morning.
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Numa Spa Meta, titles missing - updated

https://numaspa.com/product/coolsculpting/ = UPDATED
https://numaspa.com/shop/  - Cannot be updated -
https://numaspa.com = UPDATED
https://numaspa.com/blog/ = UPDATED
https://numaspa.com/reviews/ = UPDATED
https://numaspa.com/membership-program/ = UPDATED
https://numaspa.com/schedule-free-consultation/ = UPDATED
https://numaspa.com/microneedling/ = UPDATED 
https://numaspa.com/chemical-peels/ = UPDATED 
https://numaspa.com/velashape/ = UPDATED 
https://numaspa.com/skin-care-facials/ = UPDATED 
https://numaspa.com/membership/ = UPDATED 
https://numaspa.com/about-us/ = UPDATED 
https://numaspa.com/microdermabrasiondermaplaning/ = UPDATED 
https://numaspa.com/contact/ = UPDATED 
https://numaspa.com/product-category/medspa/ = UPDATED 
https://numaspa.com/product/chemical-peel/ = UPDATED 
https://numaspa.com/product/velashape/ = UPDATED 
https://numaspa.com/product/silhouette-instalift/ = UPDATED 
https://numaspa.com/product/ultimate-facial/ = UPDATED 
https://numaspa.com/product/picoway-resolve/ = UPDATED 
https://numaspa.com/product/botox = UPDATED 
https://numaspa.com/product/laser-hair-removal/ = UPDATED 
https://numaspa.com/product/frax-1550/ = UPDATED 
https://numaspa.com/product/hydrafacial-deluxe/  = UPDATED 
https://numaspa.com/product/laser-tattoo-removal-treatment/ = UPDATED 
https://numaspa.com/product/photofacial/ = UPDATED 
https://numaspa.com/product-category/medical-services/ = UPDATED 
https://numaspa.com/product/sclerotherapy/ = UPDATED 

The other links missing metas, tittles and keywords are now finished.

Numa Spa Meta, titles missing - updated

https://numaspa.com/product/dermal-fillers/ = UPDATED
https://numaspa.com/product/memberships-in-general/
https://numaspa.com/product/hydrafacial-memberships
https://numaspa.com/author/numa/ - Cannot be updated
https://numaspa.com/author/drgnumaspa-com/ - Cannot be updated
https://numaspa.com/category/spider-veins/ = UPDATED
https://numaspa.com/category/non-surgical-facelift/ = UPDATED
https://numaspa.com/category/coolsculpting/ = UPDATED
https://numaspa.com/product-category/membership/ = UPDATED
https://numaspa.com/tag/diy-coolsculpting/ = UPDATED
https://numaspa.com/tag/how-effective-is-coolsculpting/ = UPDATED
https://numaspa.com/tag/coldsculpt/ = UPDATED
https://numaspa.com/tag/coolsculpting-before-and-after/ = UPDATED
https://numaspa.com/tag/non-surgical-facelift/ = UPDATED
https://numaspa.com/tag/spider-veins/ = UPDATED
https://numaspa.com/albums/ - Cannot be updated.

Chris
I went ahead and updated their Coolsculpting page adding some LSI and search terms.
See it here -

numa spa content.png 330 KB • Download

I am done with this.