amavis Unescaped left brace in regex is deprecated, passed through in regex

I get these from the sa-update cronjob since yesterday;

Code:

Unescaped left brace in regex is deprecated, passed through in regex; marked
by <-- HERE in m/%{ <-- HERE pandoratitle}%/ at
/usr/share/perl5/Mail/SpamAssassin/Conf/Parser.pm line 1391.
Unescaped left brace in regex is deprecated, passed through in regex; marked
by <-- HERE in m/%{ <-- HERE pandoratitle}%/ at
/var/lib/spamassassin/3.004001/sa_schaal-it_net/70_SCHAALIT_header.cf, rule
SCHAALIT_HEADER_4216, line 1.

Anyone with an idea how to reliably correct these deprecated regex entries?