dovecot - Jul 2019 - Variable expansion with variables containing '%' (ldap with 2.3.6)

Hi,

there seems to be a problem when expanding variables containing a
single '%' in value in dovecot V2.3.6

having a user defined Variable in user_attrs like

user_attrs = name=home=/maildir/%Ln,
=myvar=path/%L{ldap:sAMAccountName}


and sAMAccountName conains a '%', in my example
"sonder%zeichen"
 leads to:

lda(sonder%zeichen)<5723><ov9uCHjOGV1bFgAACDoIoQ>: Fatal: Failed to
expand plugin setting myvar = 'path/sonder%zeichen': Unknown
variable '%z'

same setup works with dovecot 2.2.29

Any Feedback appreciated.
Thanks.
Matze