I understand that there is a rule (with rare exceptions) that a single word cannot bear two Masoretic accents. However, I have not seen 1 Sam. 20:25 listed as one of the exceptions:
וַיֵּ֣שֶׁב הַ֠מֶּלֶךְ עַל־מ֨וֹשָׁב֜וֹ כְּפַ֣עַם ׀ בְּפַ֗עַם אֶל־מוֹשַׁב֙ הַקִּ֔יר וַיָּ֨קָם֙ יְה֣וֹנָתָ֔ן וַיֵּ֥שֶׁב אַבְנֵ֖ר מִצַּ֣ד שָׁא֑וּל וַיִּפָּקֵ֖ד מְק֥וֹם דָּוִֽד׃
And the king sat upon his seat, as at other times, even upon the seat by the wall; and Jonathan stood up, and Abner sat by Saul's side; but David's place was empty.
I have also read that azla "occasionally replaces metheg to mark secondary stress," but I am not confident that this can logically apply here (if so how?).
What I wasn't understanding was that, with the preposition joined by maqqef, the "secondary accent" syllable receiving the kadma is not "the first syllable of the word." For Wickes, p. 113, says, "Azla may take the place of light Metheg in the same word with Geresh (only of course not on the first letter)." If this is a valid rule, then the word moshav with the two accents would be illegal, but I suppose `al-moshav is another animal.
How common is the phenomenon exemplified by the accentuation of the word moshav here?