realistic accuracy + explosion height 2 + mod Psi LoF
superhuman + max tech + sectoids + battleship + skyranger / avenger
attached below: avenger save file + skyranger save file + options for 8.5.2 - to reproduce just click "end turn" (and copy options and load) - you will see 3-4 rockets into ramp and humans will alive
(and need to translate options string - STR_BATTLEALTGRENADES)
I first tried just the saves but without your options.cfg.
The aliens weren't using the blaster at all in this scenario.
So my suspicion was that you have enabled "OpenXCom: Unlimited Waypoints". And indeed, you have. So I'm pretty sure it's related to that one.
Yup. It is. For some reason the unlimited waypoints-blaster-shots can't make it up the ramp, while the limited-waypoints-one have no problem doing so.
Now with that information I should be able to figure out the reason and make the aliens-blasters with unlimited waypoints as scary as you'd think they would be.
Edit: When I use my own soldier and place the waypoints in the same way the AI does with unlimited waypoints, it also explodes at the edge. In this sense it's almost more interesting what's different when the AI doesn't use unlimited waypoints.
What I think happens is that the missile always tries to fly through the center of the tile. But the upper-ramp-tile's center is blocked by the ramp. The non-unlimited one only places a new waypoint when either the direction changes or the Z-axis of the next pathfinding-node is different from the last one. So it will not put a waypoint at the ramp but only after the ramp.
So what I need to do is to identify that the tile I want the missile to path through has something blocking it's center and then use the tile above the current tile instead if that's the case.
Edit 2: Fix is available in 8.5.3. Oh, and I recommend maybe not using the "Unlimted Waypoints"-Mod if you don't want to be spawn-killed by aliens with Blasters.