washing machine leaks during fill cycle
The "Break Vac" is a vacuum breaker component. You'll find similar devices on sprinkler systems to avoid siphoning water back in should the water supply lose pressure, or on frost free spigots to allow water to drain out of the fixture so it can't freeze and break things. On your washing machine, the design is quite different, simply a plastic funnel sending water into the tub, but the goal is the same, to ensure water can't be siphoned back if there's a loss of water pressure. As for why yours is leaking, you'll need to do some tests to work that out.

If it's high water pressure, you can try partially closing the valves to the washing machine as a quick test, or get a cheap pressure testing gauge to see the water pressure in your home. If it's too high, you may need to have a pressure reducing valve installed where the main enters the home, and possibly an expansion tank to deal with pressure fluctuations from the water heater.

If it's in the wrong position, it should be relatively obvious when you've opened things up. On versions I've been able to find, it clips into place. If the clips are broken, then it's time to replace it. You could perhaps have a problem if the washing machine was significantly out of level.

Two other possibilities that come to mind. You could have a bad clamp holding the hose on to the back of the vacuum breaker, allowing water to leak around that connection. If so, just get a new clamp and replace it. Or there could be too much dirt and debris inside the vacuum breaker throwing off the intended water flow. You can try cleaning it to see if that corrects the issue. If all else fails, I'd just replace the part. It's relatively inexpensive and you appear to be familiar enough with disassembling your machine.