I have the Prestige Shopify theme, it has been live about a month with no issues. However, all products have just disappeared from all collections (see example: https://holmeandmoss.com/collections/womens-classic-knot-headbands).
Everything looks set up correctly in the backend and has been working fine with no issues, but they have just disappeared.
Any help would be much appreciated.
We are using the Motion theme and experiencing the same issue this morning. You can still visit an individual product page if you use the search function.
Thanks for your reply 
, looks like it’s a Shopify issue then, rather than theme specific. Have you had any luck with finding a solution?
I did just publish an old theme, then immediately published my current one, and the issue is no more! I’m not sure if that is what fixed it, or if that’s just a coincidence and it’s just fixed itself, but may be worth trying at your end?