Hi @dimalifragis, thanks for getting in touch.
As PHP Warnings are non-fatal, they don’t stop PHP or other operations from completing. You and/or your visitors won’t see any negative effects on your site.
When we’ve seen this issue come up with wfConfig.php in the past, it originates from receiving a bad value from the update_plugins transient when the site tries to check for plugin updates. The value is controlled by WordPress, but could be modified by other plugins and is stored in the wp_options table. If you have a database cache plugin, it could be worth clearing/purging the cache, otherwise make sure you have a database backup, then try repairing the database table wp_options.
If that doesn’t work, you could try temporarily disabling all plugins except for Wordfence. If the warnings stop, reenable your plugins one-by-one until the warning starts showing again in the same situation. If you’re able to narrow down a link to a specific plugin, by all means let us know so that we can run tests.
Thanks,
Peter.
@wfpeter I could do that but the problem is that this shows 2-3 times per day, so it is hard to pinpoint it.
I will try at some point and update if i found something.
Thank you