When the hourly event popped, there were about 10 of us working on it & got to about 6500 on the ‘fill-the-bar’ portion when all others where phased away. The bar was still nearly full, but I was now solo.
I made an attempt to solo the Boss when it spawned, but when that wasn’t going well I ran away. Once leashed, I returned & there were 8 billion (slight exaggeration) other players around & the event was over.
Please make phasing smarter, thank you.