Hi Séverin,
I was indeed talking about leaving the enrolment method "greyed" on Moodle 3.7, but after reading your answer (and looking at MDL-52186) I'd say that what my issue is unrelated with yours I think that my issue isn't related to the standard enrol_meta method but with the enrol_metabulk method plugin that still has that same bug from MDL-52186 (we use them both, sometimes even mixing them), so I've just done a port of that fix to enrol_metabulk.