Comment # 2 on bug 1178153 from Oscar Laborda

I have tried uninstalling the package Arduino and installing it back and it
correctly creates the symlink.

It is weird because when updating the system I usually end up with this
problem, needing to manually create the link. 

OK, it might be this: looking into the scriplets execution order, this link
says it is like this (source
https://docs.fedoraproject.org/en-US/packaging-guidelines/Scriptlets/#ordering)

    %pretrans of new package
    %pre of new package
    (package install)
    %post of new package
    %triggerin of other packages (set off by installing new package)
    %triggerin of new package (if any are true)
    %triggerun of old package (if it���s set off by uninstalling the old package)
    %triggerun of other packages (set off by uninstalling old package)
    %preun of old package
    (removal of old package)
    %postun of old package
    %triggerpostun of old package (if it���s set off by uninstalling the old
package)
    %triggerpostun of other packages (if they���re set off by uninstalling the
old package)
    %posttrans of new package

If I understand this correctly, when an Arduino package update happens, it will
first trigger %post of the new package, which will overwrite the the symlink,
and afterwards trigger %preun of the old package, which will remove the
symlink. So no symlink after the upgrade.

Is this correct?
TBH I don't quite understand how it is possible to install the new package
before removing the old one.