Hey bulbi...so farmerB had PM and it didnt remind me anything of that, or bud rot. Youre early enough in flower that neem oil could be used...but, im thinking it may be spotting due to the cold temps, not be fixed by it. Can you change its night time temp at all? Even your daytime temps a bit low and in the range where a mold and fungus would thrive, less than 65 i believe.
If it reminds me of any fungus it'd be septoria, which wether it is or isnt, you wanna get in there and remove the affected leaves and dont let them touch eachother or anything else or it can spread.