Thank you for your question.  Now is not the ideal time to plant or transplant your rhododendron.  During dormancy or early spring are the best, as this Extension article explains:  https://catalog.extension.oregonstate.edu/fs12/html

I am unable to see the leaves very clearly, but they appear to have yellowing.  Are you able to send a closeup photo of one, top and underside?  You may have other issues going on in addition to or other than the sun, as I can detect no "sunburns."  Thank you!

I am afraid what you attached were the same two you sent before.  Could you please try again?  Thank you!

Those are great, thanks!  My concern was that you might have azalea lace bugs, but I see no black dots (fecal droppings) under the leaves. But your plant appears to be chlorotic--lacking in nitrogen which causes yellowing.  You should consider applying a fertilizer with a 10-10-10 or 10-5-5 nutrient capacity and watering well during this dry season, regardless of whether you transplant now or delay until the optimal season.  Getting a soil test might help as well:  https://catalog.extension.oregonstate.edu/em8677

Good luck!

Great!  Just know that rhododendrons need acidic soil--5.5--and if the soil is closer to neutral (7.0), they cannot absorb nutrients.  That's why a soil test might be helpful, especially if the lab gives you advice about adding soil amendments (sulfur, to acidify it, for example).