Was curious if any caregivers out there have had any problems using Periguard and having it turn lumpy, like small curd cottage cheese?

I looked it up..(by the way it is available at Walmart so if you are paying extra through a medical company you can get it for less)
It has antimicrobial properties. (did not look at ingredients but probably the same as what Athletes foot and Jock Itch products have) it also contains zinc and aloe.
These products were pretty heavy on my Husbands skin so I always cut them about 50/50 with A & D ointment.

And do not rub the product in pat it on. That leaves a lighter more easily removed layer and patting it is more gentle than rubbing.

For the particular one you have I would contact both the Supplier (Vitality Medical) and complain about it and I would contact the manufacturer. It is possible that the product was stored improperly causing it to change.

This is a zinc oxide cream? It's not one I've ever heard of, most people who are thrifty shop the baby department for those kinds of creams/ointments (adult incontinence products are essentially the same at a higher price point). It could be a bad batch or could even possibly be a counterfeit, I would stop using it.