Help please!

So I originally replaced my ecu / wiring harness due to a p3030 code “ high voltage line snapped” never had an issue with my cells. Code would come on once every 2 weeks or so but drove fine. So I replaced it anyways. Battery started to act funny even with dr Prius. Would be super choppy interphase and even faulted block 2 to be bad. I put my old one back on, now instead of block 2 to it went to block 7?? I ordered a new wiring harness just in case this one I ordered was faulty. Put the 2nd “new” harness on and I’m still getting a weird charge from block 7 even tho I replaced the cells in that block today. I’m still getting over a .5 voltage difference. Did not have a voltage issue before hand. I’ve worked on the battery numerous of times and I can’t figure out this issue. Already tried replacing ecu / wiring harness and even both cells in block 7 just to see and I’m still getting weird reading. Any idea why??