You're right. Your firewall is as solid as ever.

Liteply is not always going to fail. But it has almost no excess strength at all. And it is very subject to poor internal integrity. And there is little or no way to check to see if the interior ply is even there. And it is very easily crushed by compression. It is seldom composed of even one layer of hardwood in it's three layers. And two of the layers are usually nothing more than veneer thickness.

It's use is high risk for firewalls.

Will it always fail for everyone? Nope.

Is it a smart choice of material to use in a firewall? Nope.

Since the experienced guys at the field discovered the almost universal use of Liteply in ARF firewalls, we've been inspecting them fairly regularly. And every one of us has found motor mounts crushing into them, cracking across them away from the mounts, and every one of us has had reason to reinforce at least one firewall in an existing model. And they all had a firewall that was as solid as ever.

Liteply is marginal as a firewall. It's easier to apply a layer of aircraft ply when building than later. Thin aircraft ply, just one layer, seems to be perfectly adequate to make up for Liteply's weaknesses. Why the ARF mfg's don't use just one layer in the pair they almost universally install is beyond me.