So yeah, I'm pretty sure this is a bug but in my Village of Shadows playthrough I died several times in the Lycan den. At one point, an enemy did a death from above attack that knocked me to the floor below then proceeded to almost immediately kill me.

Upon restarting at the Lycan den, with the exception of the two shielded lycans not another lycan spawned throughout the entire ascent. I don't have a video of what I did but maybe someone can make something of it.

However, this also led to a softlock in the following boss fight against Urias. Urias simply just doesn't show up.

I encountered this bug as well. Before entering the stronghold I ran back towards the Village to see if it would despawn the enemies guarding the gate, which it did. When I entered the stronghold, there were enemies in my first attempt, but when I died and respawned, just the 2 large Lycans were there, and no others. Not sure if this is related either, but I did fall onto the bottom floor the moment after the first large Lycan spawned. When I reached Urias he was not there, but I had saved in the room before, and when I reloaded he spawned in just fine.

"However, this also led to a softlock in the following boss fight against Urias. Urias simply just doesn't show up." That's actually incredibly interesting, someone yesterday on the forums talked about managing to skip the entire Strum fight by backtracking through the factory picking up items, but unlike you they were able to progress, maybe because the locks on the doors only lower when Strum appears? It looks like @hazeblade encountered this bug by backtracking too so these could be related.

I managed to get this softlock in my casual hardcore playthrough by simply clicking on Restart while fighting the boss. The pillars weren't there and he never spawned, restarting from the menu fixed it.