sport cali fluid seepage bleeder nut

[Zxces50]

Day two Session 3&4- Did back to back HPDE 3 then lined up in pit and went right back out HPDE 2- ~ 40 minutes, NJ Motorsports park- 2 Mile , 10 turn, Sunny 93-95 F-
In paddock noticed some brake fluid (maybe 10-15 drops) ran down side of stock sport cali (both fronts not rear- also same amount both fronts) started at bleeder nut but could not really tell if via threads of bleeder "hole"- very very small amount - this is track season two / 10 track days completed- did a back/back at Watkins Glen but did not have this occur. Absolutley NO change in braking, pedal feel, stopping power on track. Resevior same level - did not seem excessively hot.

"Leak" ran straight down cali-ie not wind blown thinking may have occurred just after when I entered paddocked/ finished session??

Hesitant to just tighten bleeder nut as did not happen any previous time and I have not bleed recently so that should have changed. Thinking maybe heat expansion of alum cali different than bleeder nut so got some seepage. Anybody see this before??

Running- HP + pads, ATE Super Blue, SS Lines -
The stock rotors do have a blueish tint so I gotem hot