not sure what happens here, maybe the >1 network cards creating some problem here
some fix
Code
[Unit]
Description=cifs mount script
Requires=network-online.service
After=network-online.target
Before=kodi.service
[Mount]
ExecStartPre=/bin/sleep 5
What=//192.168.2.98/Share/Plex/DVR
Where=/storage/recordings
Options=username=XXXXXXX,password=XXXXXXXXX,rw,vers=2.1
Type=cifs
[Install]
WantedBy=multi-user.target
Display More
add an delay to the mount script (5sec ... or whatever works)
ExecStartPre=/bin/sleep 5
not sure if this works but I guess you can easily try this