Is there something going on with my sunflowers or am I paranoid?

I've noticed on some of my sunflowers there is a brownish coloration on the stalks that is accompanied with yellowing/browning wilted leaves. The leaf damage is for the most part at the bottom of my stalks where the older leaves are, but up top where my larger more healthier leaves are at I'm beginning to see discoloration that looks similar. Things like yellow spots and browning/wilting tips are showing up, and combined with whatever is going on with the stalks I'm fearing it may be a disease like verticillium wilt or some other affliction. I've asked others and they say that the plants seem very healthy and thriving, but I've yet to get an answer (or even guess) as to what is going on with my stalks. Is it really nothing, or have I got the jump on a blight that could kill some of my plants? Sorry for some of the night time pictures, I didn't notice until doing a walk around just as the sun was setting

Not sure where you are located which can influence which diseases may be most prevalent.  There may be something helpful in this link although it's pretty full of possibilities:  https://www.ag.ndsu.edu/publications/crops/sunflower-disease-diagnostic-series

If you start seeing some expansion of the disease on the stems and leaves and happen to have a horticultural/agricultural extension service nearby, they can often be quite helpful in determining causes and possible solutions.  Good luck!

Well based on that link things seem a little bleak, but I'll definitely touch base with an agriculture service! I've never done so before, but is it usually as simple as just shooting them an email with pictures and asking them what they think? I'm in Dallas so Texas A&M is mine, I suppose I lucked out in that sense!

I see you have a drip line...how much water are they getting/ daily/ and what is your weather like

I've been watering them once a week for around 25-30 minutes. Weather has been sunny, dry, and hot (low to mid 90s). We had a thunderstorm blow through four or five days ago, but there wasn't really a torrential downpour associated with it