Hermetia illucens - dangerous?

[MantisRCool]

Hello, I have question about these weird flies. Me and my friend bought them and after eating them, many of my friend's mantids died! I didn't use them much cause they kinda seemed weird to me and didn't come out of their box as normal flies so I was like too lazy to get them out lol. But one gongylus died, and when I cut her belly there was this gross stench of dead flies. 

But a lot of my friend's mantids died after feeding them these flies. 

What are your experiences with those? I know I'm not gonna buy them anymore.

 

[Teamonger]

I just started feeding my mantises these flies. I am breeding them myself however so I know exactly where they came from and what they are eatting. No problems so far but its only been a few days. I'll let you know if anything bad happens but I doubt it.