Impossible to insert

[totonicknick]

Looking at your code, test if this solves your problems:
Add a first line of the Sub ConditionalFormating(Target As Range, j As Integer) sub:
Target.Parent.Cells.FormatConditions.Delete

Only doing that doesn't work.
However, removing all previous conditional formatting before updating worked perfectly, thank you!
For now, I have deleted all previous conditional formatting AND added the line you recommended.
Hopefully this will prevent it from happening again, but if it still happens at least I know how to solve it

I'll put this thread as "solved".