Comment # 9 on bug 1082704 from Peter S�tterlin

I definitely have different packages, as I am running Tumbleweed, whereas yours
seem to indicate Leap.  I just re-downloaded the rpm package from nvidia and
checked the scripts again, they are identical, and the postinstall only has the
mentioned call to /usr/lib/module-init-tools/weak-modules2

And while I did have a look at the triggers of the kernel-default-devel package
(there are none), I forgot to do the same for the nvidia pakage :((

And indeed, they show what I suspected:

--------
triggerin scriptlet (using /bin/sh) -- kernel-default-devel
flavor=default
pushd /usr/src/kernel-modules/nvidia-390.25-$flavor || true
cp -a Makefile{,.tmp} || true
make clean || true
mv Makefile{.tmp,} || true
popd || true
arch=x86_64
flavor=default
kver=$(make -sC /usr/src/linux-obj/$arch/$flavor kernelrelease)
make -C /usr/src/linux-obj/$arch/$flavor \
     modules \
     M=/usr/src/kernel-modules/nvidia-390.25-$flavor \
     SYSSRC=/lib/modules/$kver/source \
     SYSOUT=/usr/src/linux-obj/$arch/$flavor
pushd /usr/src/kernel-modules/nvidia-390.25-$flavor 
make -f Makefile \
     nv-linux.o \
     SYSSRC=/lib/modules/$kver/source \
     SYSOUT=/usr/src/linux-obj/$arch/$flavor
popd
install -m 755 -d /lib/modules/4.15.2-1-$flavor/updates
install -m 644 /usr/src/kernel-modules/nvidia-390.25-$flavor/nvidia*.ko \
        /lib/modules/4.15.2-1-$flavor/updates
depmod 4.15.2-1-$flavor
---------

It compiles for the latest kernel (kver resolves to 4.15.4-1-default), but then
installs the modules to the (fixed) location of the old modules. 

IMHO the install should go to /lib/modules/$kver/updates