tremolos not playing properly

Hello,
I was composing a quintet but then the tremolos (with double-stops) aren't playing properly.
It sounded like the double-stops are echoing without tremolos.
The tremolos with normal and single notes were fine, but I wanted to make it with double stops and chords.
Is there any way I can fix this?
(see attachment below pls to test)
Thx