Hi GoatOfDeath,
I retested the exact repro the original poster provided and the issue doesn’t occur in 4.14.3. So I believe what you are seeing is a similar but different issue.
First, try retesting it in the latest 4.16 Preview.
If it still happens and it specifically deals with ‘child blueprint variables’, please read this Forum post and comment there if you think it’s the same issue.
If not, please create a new post in the Bug Report section of AnswerHub and provide exact repro steps and/or a small test project.