Event lost during upgrade on 2018.4.12 to 2018.4.16 LTS...

Hello guys,
we just upgrade our project from 2018.4.12 to 2018.4.16 LTS (which is a LTS so stability must be here...)
and we noticed some prefab lost their Event in some OnClick when they were set into the prefab.

We thought it's related to this issue :
https://issuetracker.unity3d.com/is...54.2037876953.1580715518-260204955.1565765333

@LeonhardP have you any idea in which LTS it will be fixed ?

Cause in the issue tracker you (unity team) write Fixed in 2018.4 but no minor version are mentionned so it's hard to know when...
The bug is present for 2 months now and it's pretty bad to see a bug like this one in a LTS version for so long