Refresh template variable when other template variable changes - fail sometimes


From what I found here :

A template variable is supposed to refresh when the parent variable changes…
It works most of the time for me, but for one it doesn’t.

Both parent and child are query type, and I tried the 3 refresh modes for the child.
My only way to have this variable refreshed is to go edit it and just update.

Can you give me a hint on this ?