Currently you can shoot a stick of C4, detonate another C4 on top of the 1st one, detonate grenade next to it - it won't explode.
Luckily this is easy fixable with 1 line of code in config file so please devs do us a favour and add this to the config
class DemoCharge_Remote_Ammo: PipeBombBase
{
triggerWhenDestroyed = 1;
};