SUBJECT_IN_WHITELIST triggered by spamassassin

I’ve got two MIAB servers. Some time ago, I successfully configured the first one to whitelist a subject that was wrongly being flagged as spam. I forgot to document my change and I’m having trouble recreating the setting on my second MIAB for another domain.

The mail headers from the box that is working looks like this…

X-Spam-Checker-Version: SpamAssassin 3.4.2 (2018-09-13) on
X-Spam-Status: No, score=-80.9 required=5.0 tests=DMARC_FAIL_REJECT,
	TVD_SPACE_RATIO shortcircuit=no autolearn=no autolearn_force=no
	*  5.0 SPF_FAIL SPF check failed
	*   10 DMARC_FAIL_REJECT DMARC check failed (p=reject)
	* -0.0 SPF_HELO_PASS SPF: HELO matches SPF record
	* -0.0 SUBJECT_IN_WELCOMELIST Subject: contains string in the user's
	*      welcome-list
	*  2.0 PYZOR_CHECK Listed in Pyzor
	*      (
	*  0.0 TVD_SPACE_RATIO No description available.
	*  0.1 MIME_HEADER_CTYPE_ONLY 'Content-Type' found without required
	*      MIME headers
	*  2.0 MIME_NO_TEXT No (properly identified) text body parts
	*  0.0 TO_EQ_FM_DOM_SPF_FAIL To domain == From domain and external SPF
	*       failed
X-Spam-Score: -80.9

I believe this line in triggers spamassassin to score the message (with -100)

me@box:/etc/spamassassin$ grep whitelist_subj 
whitelist_subject Voice Message

However, the same line in the same file on my second MIAB is not giving me the same result. The headers don’t indicate that SUBJECT_IN_WHITELIST is being triggered at all.

Is there something I am forgetting to do besides updating ?