Spawn Rate Averages

On the contrary for me then, scraps exp. sledgehammer and even gets it from FNIX hunters turned Rivals.

Lost count of how many Exo armor thingys I and Flakmoped skins I got from Reapers after Skyfall release but only 1 exp. Meusser from 5 or 6 Vultures.

It’s something like that but also not. What class changes what a machine gives but also it feels like some,
for example a FNIX Hunter, gives totally different loot depending on where you meet it. FNIX hunters can be found in all regions except the Archipelago region now. The ones on Himfjäll and in Forest and Marshland gives me both Exp. and 5C weapons fairly regularly. In the other it has to be a rival to give a 4C weapon otherwise you only get 2C’s or 3C’s from them.

if they don’t just disappear into thin air before your eyes in the current situation of the game.

That is exactly what I was stating, the same machines in different areas will produce different loot. It is quite common for hunters of all classes and all locations to have steel and runners, lead. The hunters and runners on the island, it is common they have ammo for automatic weapons.