Your Zurich ZR13 scantool can graph up to 2 PIDs simultaneously. It would be very helpful if you could post a screenshot of your scantool while graphing the "O2S B1S1" and "O2S B1S2" voltages, either individually or (preferably) together.
Be aware that the steady 99.2% you're seeing for PID "STFT B1S2" means that that particular STFT value is meaningless -- 99.2% is how it says that that sensor is "not used in the calculation", which makes sense because "STFT BxS2" would be the PID associated with a downstream sensor.
In general, be reasonably careful with your interpretation and reporting of these PIDs. It can get quite confusing because the OBD2 standard (and, hence, your scantool) PIDs include STFT for a given bank in 3 places -- STFT for the bank, STFT for the upstream sensor on the bank (which always seems to match the former value, in my experience), and STFT for the downstream sensor on the bank (which is the meaningless PID I refer to above). Personally, I would focus only on the 1st value for STFT (i.e. what your scantool reports as "STFT B1", per the 1st image in your 1st post).
EDIT: Removed references to "Bank 2". I forgot that we're talking about a 2.3L engine here, which has only 1 bank, as your latest screenshot with the "O2SLoc" PID made clear!