The mesh painting mode appears to no longer work on splines, as the vertexes seem to have all vertex colors at 1, 1, 1, 1 by default, and can't be removed or painted anything else.
There's no existing public thread on this issue, so head over to Questions & Answers just mention UE-186643 in the post.
|Component||UE - Editor - Content Pipeline|
|Created||May 22, 2023|
|Updated||May 30, 2023|