Leaves on Jack Herer autoflower plants have darker purple/brown spots

From a fellow grower: harvested my first Jack Herer autoflower plant and hung to dry for 2 weeks indoors – temp stayed around 67-70 and humidity around 65-70% ish assuming the hygrometer is accurate. I tried to keep constant airflow but don’t have a fancy set up right now or a dehumidifier so couldn’t get much lower than 68-70% (will be using humidity packs for curing). The stems were crackling when I bent them.

I went to trim them yesterday and noticed that some of the undersides of the stems/leaves had turned a dark purple/brown color. This seemed odd to me as I have never known Jack Herer to have purple coloring and this didn’t look like anything I’ve seen before.

I got extremely nervous but didn’t find any white/grey/fuzzy mold or anything that looks like the images I’ve seen of bud rot form my research. There is no bad or musty smell – it smells amazing!!

Is there a normal reason why the color would darken in some spots like this or should I be concerned it is mold or fungus? I looked under a 30x magifying glass and didn’t see any fuzzy mold. I also tried looking under a 60x jewelers loupe and from what I could see the trichomes looked normal up close. I tried breaking some areas open and didn’t notice any obvious bud rot/mush/spores but I know it isn’t always easy to detect. It seem like it is primarily on the bottom stems and undersides of the sugar leaves, but also noticed the bottom portion of a lot of the buds are darker than the tops.