This may be totally off base but I see utility lines in the background and they appear fairly close to the tree. Does the utility companies in your area spray to control folliage around lines? Reason I ask is they do spray around here where I am and this damage looks just like what I see after they have sprayed.

I don't have a lot of weed to worry about. Whenever I see them I either yank 'em up by hands or spray a weed killer. None was near this citrus. I must add this info, though. I've had this tree for about 1.5 years. Initially right after planting, it was infected with some type of bugs, all the leaves dropped,bare branches remained for many months, I thought the tree was dead. All the branches at that time were covered with some shiny, waxy residue, very sticky to the touch. I removed most of those brances, leaving the few large ones. Then as if returning from the dead, new leaves started sprouting up. Those are the healthy ones you see in the photos. The last 2-3 weeks have seen the new leaves. While not curled up initially, didn't take long for them to do so. I checked the plant very carefully the last several days, didn't see any bugs. I do notice that the grasshoppers like to hang out on the plant, and there are the occasional spiders. Any thoughts are appreciated,

so you moved it from inside to full sun? That sounds like sunburn. You need to move plants gradually into the sun. I would trim off the dead leaves and move it to a shadier location, edging it out into the sun over the course of a week or so.

Well, the problem just started a couple of days ago but it definitely seems to be "reproducible at will." I've tried it at least half a dozen times today. It keeps recurring every single time. Once the problem starts, I have to let everything cool off for awhile before I start the shower back up again or it will go wonky immediately instead of behaving normally for the first couple of minutes. I tried turning the master shower on first and then turning the guest shower on and everything ran normally for several minutes... longer than usual, I think. But, as soon as I turned the master shower off, the guest shower immediately started acting up. As in, it started going wonky the EXACT SECOND that I turned the master shower off. After that, even if I tried turning the master shower back on, the guest shower continued to be wonky. I'm thinking I should probably try the experiment again, maybe wait quite a bit longer to cut the master shower off to make sure that the "exact second" start of the problem wasn't merely coincidental? I'll rerun the experiment in half an hour or so, as soon as the water in the lines has had time to cool off and will let you know what happens. I will also try the experiment the way you suggested. I.e., turn the guest shower on first and then turn the master shower on. Should I wait until the guest shower starts acting wonky to turn the master shower on to see if turning the master shower on seems to correct or at least minimize the problem? Or, should I turn the master shower on as quickly as I can manage to get from one room to the other to see if having the master shower on, keeps the guest shower from going wonky? Or, should I try both ways? There has not been any remodeling done. This is the original plumbing that was put in when our new house was built four years ago. So if there is an error in the way the plumbing was run, it is a mistake that was made by the plumbers hired by our builder. But, given some of the other problems we've run into with this house, I certainly would not try to argue that "contractor error" can't be involved. I'm afraid I have no idea where the shut-off valve for the shower would be located. There is no "access panel" for either shower. I do have open wall photos taken during the build so, if I knew what to look for, I might be able to figure out where the shut-off valve (assuming there is one) is located. Since there is no access panel, does that support the idea that the shut off valve for the vanity sink may also be serving as shut off for the shower?