As much as I'd love to shift blame to something high level like Unity, I have a feeling it's just as likely some tiny stupid oversight on our part.
Not saying it's all Unity's fault. Most likely something you coded works for others and in a few cases fails due to circumstances wich may or may not be linked to Unity either alone or in cunjunction with whatever. If i thought it was all Unity failing me i'd not have told you i hope it may help.
I only pointed my past issues with Unity for if you ever want to look down that path...
Managed to get past that point in the game anyway, and that's what currently matters to me. ^^