Ver 1.9.0, period, new install, early game when discovered.
I deployed a thermal buoy using launch ready ordnance, the buoy has strength 1.07 sensor. Despite zooming in many mouse wheels of zoom, no passive detection ring shows up (not even with Passive vs Signature 10,000). The View Technology window shows the expected information for the buoy. However, on tactical, above the buoy is a label "Active: 0m R100". I did design some active buoys prior to designing the thermal buoy but the thermal buoy in question definitely does not have an active sensor.
Thanks,
PS: TN start, real stars (sorry forgot that above)