EC is crazy high for this stage, example is i max out at 1.4-1.5 in peak flower with huge plants. That needs about 1.0 EC and probably get away with 0.9. Also raise light for a few days till recovered. Ph and everything else looks good although raise it to 5.8 just to rule that out.
Feel free to check my hydro diaries to get a idea of my EC levels, less is more sometimes brother👍