Replaced rear 02, still throwing CEL codes?

[kkeiran]

2003 Ford Focus SVT, 2 Door Hatchback.

I replaced a bad 02 sensor this morning (it was bent against pipe above) which was throwing codes P0141 & P0136. I'm usually not concerned too much about the rear sensor as my car eats through them like candy anyhow, but I need to get it to stop throwing the CEL codes so I can pass inspection. Usually when I pop in a new sensor, everything is fine at least for a while (months?)... definitely enough time to run through inspection.

Well this year things aren't going as planned. I know Bosch aren't the best quality, but it's all we have locally and they've always worked fine at least for a bit. Anyway, I installed a new one (rear, sensor 2) and cleared the code, but after driving cycle the CEL turned on again. This time it as just P0141. I double checked the installation and everything looked fine... tight, reconnected again, and no obvious signs of bad wires on either end. I clear the code again and after this drive cycle P0141 is gone, but now it's showing just P0136. :/

Is this anything else I should try before cutting my loss and assuming I got a faulty sensor? Would a bad fuse somewhere cause any of this?

I need to pass inspection soon, lol.

Thanks for your time and help.