Does the use of regexp make that field required?  I have used regexp
on a field that is not required.  If a user wishes to complete the
field I want the regex to operate but not if the user chooses not to
complete that field.  During testing, I found that the regexp produced
an inline prompt to complete the field even though it is the only
validation for that field.

The regexp is:
rules[12]='custom10:* Tu móvil o otro teléfono|regexp|^[0-9,+,(), ,]
{1,}(,[0-9]+){0,}$';

Brgds Rups