Came across an interesting fault/bug today whilst on a call on my iPhone.
Whilst I was on the call, another call came in on call waiting, but the actual call I was on went very garbled and the caller hung up.
Then I called that caller back and received another call waiting call and same issue happened, so we decided to experiment.
Each time I was on a call on VoLTE the existing call would go very garbled, almost like a bandwidth issue. Roll back to 3G and no issue at all. And we tried from different carriers and also from VOIP. Still the same issue.
Then swapped to a Vodafone Sim, no issues at all with Call Waiting, so assuming some kind of Spark issue/bug.
Ive raised a fault with them to investigate, but thought I would seek the opinions of the community to see if anyone else has had the same issue.
Oh and just to note, I am using an eSim for Spark in an iPhone XS Max.