Help with losing decal textures?

Occasionally my decals all become unhappy. I've created new decals with materials, properties, etc. They work for a while, then I'll notice that they've been replaced by example_missing in the decal manager and the instances all have properly dimensioned "No Material" textures. Fortunately I don't have many decals (maybe 6 instances total).

I'm not sure what I'm doing to cause this... Any pointers?

Here's a snipped of beamng.log, see "Dirt_Curve_missing" as an example....

Help with losing decal textures?