I am sure that there are different species of each type of snails so not saying that all of them within any group do this...but some Trumpet snails do not limit their eating to dead plant matter. I had a tank full of vals which trumpet snails killed by eating off the roots thereof. FWIW....I have never heard this about Malaysian Trumpet snails.
The ones which did this were "collected" from natural sources in southern Louisiana.
But I appreciate your thread as many do panic over something which, for example might keep the algae off of the leaves of an Anubias plant.
Thanks for your comment Raymond. I'll try to find out more about that type you heard about, but I'm glad it wasn't the common MTS you see all around.
If I find anything I'll be sure to post it here.