On my Leap 15.0 running transactional server, options field is too long for
systemd to handle it properly:

overlay                                    /etc                    overlay 
defaults,upperdir=/sysroot/var/lib/overlay/168/etc,lowerdir=/sysroot/var/lib/overlay/167/etc:/sysroot/var/lib/overlay/166/etc:/sysroot/var/lib/overlay/165/etc:/sysroot/var/lib/overlay/164/etc:/sysroot/var/lib/overlay/163/etc:/sysroot/var/lib/overlay/162/etc:/sysroot/var/lib/overlay/161/etc:/sysroot/var/lib/overlay/160/etc:/sysroot/var/lib/overlay/159/etc:/sysroot/var/lib/overlay/158/etc:/sysroot/var/lib/overlay/157/etc:/sysroot/var/lib/overlay/156/etc:/sysroot/var/lib/overlay/155/etc:/sysroot/var/lib/overlay/154/etc:/sysroot/var/lib/overlay/153/etc:/sysroot/var/lib/overlay/152/etc:/sysroot/var/lib/overlay/151/etc:/sysroot/var/lib/overlay/150/etc:/sysroot/var/lib/overlay/149/etc:/sysroot/var/lib/overlay/148/etc:/sysroot/var/lib/overlay/147/etc:/sysroot/var/lib/overlay/146/etc:/sysroot/var/lib/overlay/145/etc:/sysroot/var/lib/overlay/144/etc:/sysroot/var/lib/overlay/143/etc:/sysroot/var/lib/overlay/142/etc:/sysroot/var/lib/overlay/141/etc:/sysroot/var/lib/overlay/140/etc:/sysroot/var/l
 ib/overlay/139/etc:/sysroot/var/lib/overlay/138/etc:/sysroot/var/lib/overlay/137/etc:/sysroot/var/lib/overlay/136/etc:/sysroot/var/lib/overlay/135/etc:/sysroot/var/lib/overlay/134/etc:/sysroot/var/lib/overlay/133/etc:/sysroot/var/lib/overlay/132/etc:/sysroot/var/lib/overlay/131/etc:/sysroot/var/lib/overlay/130/etc:/sysroot/var/lib/overlay/129/etc:/sysroot/var/lib/overlay/128/etc:/sysroot/var/lib/overlay/127/etc:/sysroot/var/lib/overlay/126/etc:/sysroot/var/lib/overlay/125/etc:/sysroot/var/lib/overlay/123/etc:/sysroot/var/lib/overlay/116/etc:/sysroot/var/lib/overlay/115/etc:/sysroot/var/lib/overlay/114/etc:/sysroot/var/lib/overlay/113/etc:/sysroot/var/lib/overlay/112/etc:/sysroot/var/lib/overlay/111/etc:/sysroot/var/lib/overlay/110/etc:/sysroot/var/lib/overlay/109/etc:/sysroot/var/lib/overlay/108/etc:/sysroot/var/lib/overlay/etc:/sysroot/etc,workdir=/sysroot/var/lib/overlay/work-etc,x-systemd.requires-mounts-for=/var,x-systemd.requires-mounts-for=/var/lib/overlay,x-systemd.requires-m
 ounts-for=/sysroot/var,x-systemd.requires-mounts-for=/sysroot/var/lib/overlay,x-initrd.mount
 0  0  

(I've updated read-only-root-fs to latest git version, leap 15.0 version was
preventing /etc to be mounted read-write).

>From the logs:
/run/systemd/generator/sysroot-etc.mount:15: Unknown lvalue 'unts-for' in
section 'Mount'


/run/systemd/generator/sysroot-etc.mount:
# Automatically generated by systemd-fstab-generator

[Unit]
SourcePath=/etc/fstab
Documentation=man:fstab(5) man:systemd-fstab-generator(8)
Before=local-fs.target
RequiresMountsFor=/var /var/lib/overlay /sysroot/var /sysroot/var/lib/overlay

[Mount]
Where=/etc
What=overlay
Type=overlay
Options=defaults,upperdir=/sysroot/var/lib/overlay/168/etc,lowerdir=/sysroot/var/lib/overlay/167/etc:/sysroot/var/lib/overlay/166/etc:/sysroot/var/lib/overlay/165/etc:/sysroot/var/lib/overlay/164/etc:/sysroot/var/lib/overlay/163/etc:/sysroot/var/lib/overlay/162/etc:/sysroot/var/lib/overlay/161/etc:/sysroot/var/lib/overlay/160/etc:/sysroot/var/lib/overlay/159/etc:/sysroot/var/lib/overlay/158/etc:/sysroot/var/lib/overlay/157/etc:/sysroot/var/lib/overlay/156/etc:/sysroot/var/lib/overlay/155/etc:/sysroot/var/lib/overlay/154/etc:/sysroot/var/lib/overlay/153/etc:/sysroot/var/lib/overlay/152/etc:/sysroot/var/lib/overlay/151/etc:/sysroot/var/lib/overlay/150/etc:/sysroot/var/lib/overlay/149/etc:/sysroot/var/lib/overlay/148/etc:/sysroot/var/lib/overlay/147/etc:/sysroot/var/lib/overlay/146/etc:/sysroot/var/lib/overlay/145/etc:/sysroot/var/lib/overlay/144/etc:/sysroot/var/lib/overlay/143/etc:/sysroot/var/lib/overlay/142/etc:/sysroot/var/lib/overlay/141/etc:/sysroot/var/lib/overlay/140/etc:/sysro
 ot/var/lib/overlay/139/etc:/sysroot/var/lib/overlay/138/etc:/sysroot/var/lib/overlay/137/etc:/sysroot/var/lib/overlay/136/etc:/sysroot/var/lib/overlay/135/etc:/sysroot/var/lib/overlay/134/etc:/sysroot/var/lib/overlay/133/etc:/sysroot/var/lib/overlay/132/etc:/sysroot/var/lib/overlay/131/etc:/sysroot/var/lib/overlay/130/etc:/sysroot/var/lib/overlay/129/etc:/sysroot/var/lib/overlay/128/etc:/sysroot/var/lib/overlay/127/etc:/sysroot/var/lib/overlay/126/etc:/sysroot/var/lib/overlay/125/etc:/sysroot/var/lib/overlay/123/etc:/sysroot/var/lib/overlay/116/etc:/sysroot/var/lib/overlay/115/etc:/sysroot/var/lib/overlay/114/etc:/sysroot/var/lib/overlay/113/etc:/sysroot/var/lib/overlay/112/etc:/sysroot/var/lib/overlay/111/etc:/sysroot/var/lib/overlay/110/etc:/sysroot/var/lib/overlay/109/etc:/sysroot/var/lib/overlay/108/etc:/sysroot/var/lib/overlay/etc:/sysroot/etc,workdir=/sysroot/var/lib/overlay/work-etc,x-systemd.requires-mounts-for=/var,x-systemd.requires-mounts-for=/var/lib/overlay,x-systemd.re
 quires-mounts-for=/sysroot/var,x-systemd.requires-mounts-for=/sysroot/var/lib/overlay,x-initrd.mount