You should fix that error. A proper version of that file shouldn’t even have a line 8.
As a first fix I’d try disabling the repo using
ssu dr. Second step, remove it with
ssu rr. If it doesn’t help simply delete (with backup) this file. Do a pkcon refresh after each try.
For reference, here’s the content of that file on my device:
[nubecula-mls-offline-repo] name=nubecula-mls-offline-repo failovermethod=priority type=rpm-md gpgcheck=0 enabled=1 baseurl=plugin:ssu?repo=nubecula-mls-offline-repo