I had some spotting of brown stuff at 11DPO but then got a
a few days later when AF was late so it could be implantation. Found this info on the web:
What does implantation bleeding look like?
Most women report experiencing implantation bleeding as light spotting that's either light pink or brown in colour. Unlike menstruation it tends only to appear over a period of one - three days and is usually intermittent rather than a regular flow that becomes heavier over time.
When does it occur?
Implantation bleeding tends to occur before menstruation is expected, this is usually between six and twelve days after ovulation. Most women experience menstruation approximately 14 days after ovulation however this will depend on your individual cycle.