What accents, if any, can appear on a non-initial vocal shewa? The answer is: none, except for a misplaced tsinnorit that is seen in Psalm 32:5 ועוני in some editions. In these editions, the tsinnorit of ועוני appears on its ayin whereas it should appear on its second vav:
| wrong | וַעֲ֘וֺנִ֤י |
| right | וַעֲוֺ֘נִ֤י |
I’ve found this error in these editions:
(Both of the above editions also have a געיה on the first vav, but that is a legitimate variant. This variant reflects the more געיה-heavy style associated with the printed tradition rather than the tradition of the most authoritative manuscripts.)
(In the Chabad edition, this word has two other problems. (1) Instead of Unicode HOLAM HASER FOR VAV, it uses ZWJ followed by HOLAM. (2) Instead of MAHAPAKH, it uses YETIV. Those two problems are widespread in the Chabad edition, i.e., not specific to this word.)
The correctly-accented version of this word is typographically challenging, particularly with the “tilde” form of tsinnorit. (This “tilde” form is the form shown above.) It is challenging because the tsinnorit contends for space with a ḥolam ḥaser dot on a narrow letter, namely, vav.
(For info about how BHS meets these typographic challenges, see my document, “Tsinnorit and the Ḥolam Ḥaser Dot in BHS.”)