Black frame keep being inserted at the start

My gifs keep getting a black frame at the start, which makes the animation blink annoyingly.

I've put delay in my first entry as 0, to no effect.

records:
- delay: 0

The strange thing is, it did work a couple times! But can't reliably reproduce it anymore. I've tested all frameBox types and style combinations.

Please, how can I get rid of the first black frame?