as described in this thread, 4.19 broke the ability to work procedurally with render data at runtime.
The new LODRenderData system with seperate buffers for each vertex-property instead of arrays of FSoftSkinVertex offers Init-functions with count-parameter for all types of buffers, so you can dynamically change the number of vertices as needed. The exception is the buffer for SkinWeights. It only has an assignment operator that COULD be used instead, except it produces a linker error in editor builds, but not in no-editor builds! Correct me, if I’m wrong, but I don’t think you intended for any runtime code to produce linker errors in PIE builds, because it’s impossible to work this way. The best solution would be an Init(count) function like all the other buffers have, anyway. Please fix this. I can’t port my project anymore.