There are a number of threads with troubleshooting tips on harvesting and preventing leakage into the hive - and some strong opinions (shockingly).
https://forum.honeyflow.com/t/honey-flooding-during-extraction/8170/4
It seems that some of the common ideas relate to hive tilt and opening the frames in segments but there are some contributors that harvest remotely.
If you can post more details about your situation maybe the brain trust can figure out a solution.
Does the honey seem to leak more toward the back or front of the hive? Can you describe your set up and your method for harvest?