Psalm 61:8 - male nun in text

Here's a howdy-do

There's a word in the text of psalm 61:8 that Michael Fishbane (Biblical Interpretation in Ancient Israel) suggests is a scribal acronym about the spelling of preserve. The transcription made me laugh as I tried to express it in translation.

[Full spelling v8 (Fishbane p 61) מַן min =  מָלֵא נן male nun] Here the scribal comment on spelling has become part of the received text!

יֵשֵׁב עוֹלָם לִפְנֵי אֱלֹהִים חֶסֶד וֶאֱמֶת מַן יִנְצְרֻהוּ

8

yéshéb `volam lipnéy )elohym xsed ve)emet màn yincruhvu

he will dwell ever before the face of God mercy and truth [note the full spelling] will preserve him