Hmmm.. except for your sandy soil, don't raised beds mean you have to water more often in AZ? I'd THINK the bed that has the rosemary and thyme would be the place for the sage, it likes full sun. I can think of several reasons for it not doing well... over/under fertilization or over/under watering. Without a picture, that's the best I can do.
I had a great place for a salvia officinalis and I put two in there and they promptly died, but the thyme has happily taken over. Could be that the salvia was too root bound when I put it in there, it was too shocked when I put it in there... or even something that's in that spot in the soil.
If you need more than that, I, myself, could only diagnose better with a picture. Hope that helps some.

The raised bed simply make planting a little easier and also allows for less watering with the addition of more absorbent soil matter and additions. The ground is quite hard packed in Tucson and has a layer of Caliche (hardened calcium carbonate) at or near the surface that can only be gotten through with a pick ax or jackhammer. Thus the raised beds :)

Sorry no pic right now and its hailing as we speak, so I can't run out and take a picture.

I'm guessing its the heat and possible slight under watering . . . just because during the Summer in Arizona some plants will never get enough water or shade to make them happy.

Sage will grow and thrive in temps even higher than that, but it MUST have a drink regularly (even though the books tell you it prefers dry conditions), and it must have excellent drainage. It will do best in the garden with the rosemary and thyme, which like exactly the same conditions.

Having said that, sage can be a cantakerous plant. You can give it all the perfect conditions for it, and it will still sometimes die just to spite you, and for no apparent reason. I think it's rather sensitive to pH (that's my theory). Check that it's around pH 5.0-6.5.

I think it's most likely to be an underwatering problem, but don't overdo it. It's a plant that resents big sudden changes in its regime.

I had the feeling that it might be temperamental due to the last plant going from lush to dead in two days flat.

It is currently next to the profusely flowering thyme, so I think its in the right place.

I will water a bit more (carefully) and check the pH. Thanks!

I grew sage from seed here in Z6 and it was fine. It does need watering however. I like using soaker hoses for most watering needs. Because the winters will kill it, I harvest all of mine before a frost set in. It was dried in a dehydrator and then rubbed between my hands to break up the leaves into a fiberous mass. Its great in sausage making..

I think it's odd, though I don't live in a desert like Tucson, it's still fairly dry in Sacramento, we both have sage next to thyme in a raised bed and both were unhappy next to a happy thyme.... hmmmm.... is thyme homicidal? :D I should call the plant CSI's... see what's going on.
I have a yard full of salvia's and only the officinalis has died.

No, Heathen, I think Sage is the homicidal one! Try growing Hyssop next to it!! Both will cark it before you can blink. In my experience, anyway. Thyme is actually one of the so-called Physician Plants - it improves the health of other plants nearby (and encourages weed to do well, too!).

Yes, other salvias grow like weeds of the can't-kill-'em variety.

lol Sage is either homicidal or suicidal. Makes me giggle. Perhaps our brief monsoonal downpour yesterday will help a bit (unusual for us to get rain in May).

Sage has been a problem plant for me as well, which really bugs me. Rosemary, pineapple sage, and lemon verbena come back for me every year (and that's really pushing the envelope for those last two here in zone-7 ABQ). But regular old sage never comes back.

My mother, who lives in zone-6 Utah, has HUGE sage plants along her driveway. And she doesn't do anything special. Grrr. I'll have to get some starts from her this summer when I visit. I did start a couple new plants this year, we'll see...