It's almost certainly to do with your particular third party plugins. That is why nobody else is reporting it, and plugin developers very frequently make this type of mistake. I guess failing to report the errors is a separate issue.
There's nothing wrong with cf_deprecated or af_deprecated on their own, but ef_deprecated is invalid on its own because C2 still needs to know the return type of the expression since it can still be used by existing projects! So it must be combined with one of the return type flags, but plugin developers frequently replace the flag and make that mistake.
Similarly a plugin can't say it is a "world" type if it specifies pf_singleglobal, probably just another addon developer mistake.