Space at the start of end of an email address are not actually port of address it self but may be allowed in certain syntactic contexts due to how the RfC 5322 specification si written.

According to RFC 5322, the adreess spes( which different the email address format) can be surrounded by comments or folding with space (CFWS) wich in cludes optional spaces tabes, or line bresks,

this is not because space or valid in side an email adress but because CFWS is peimitted around certain components ,such as the local party or domain. so technically:

me @domain.com (comments)

RFC 5322 define an email adress an addr- spec, and and this allow option, comments and following white space (CFWS) in some positions. T