Is that mold?

looks like bird shit. lol. looks to be something that dripped on it basedon 2 spots on left. can tell the liquid shifted due to gravity before drying, which a wpm spot would not do. it would already be spreading if a colony was that size, too. got plenty of foliage. carefully remove if worried. a colony is spreading spores within 5-7 days of getting a foothold. things that clean the surface do not rid the plant of the infection, sadly. horticultural oil can slow spread. some things change leaf surface pH. None of it is very effective. even the heavy-duty fungicides are terrible at what they are supposed to do. amputate, spray down with something anti-fungal and pray when you do get an infection. especially with 13 plants, if you know you are catching it early it's almost better to kill the plant. definitely amputate more than necessary around the infection. wrap it up before doing so so the agitation doesn't help spread spores. I'm 99% sure this is not wpm. unless you see differences in person between the 2 spots on left from the more circular one on right. looks more like a stain when zoomed in.

Could be wpm white powder mildew. A mixture of homogenized milk and water. 60% water 40% milk in a spray bottle can help keep it under control