I'd like to clarify a few things for those who don't understand the complexities of reconstructing BH phonology. The Tiberian system we read in our printed versions (or those who read the facsimile of Leningrad or Aleppo) is medieval and reflects a different vowel phonology than we reconstruct for biblical era Hebrew. The Tiberian vowel phonology is based (mostly or exclusively, depending on who you read) on vowel quality. There are seven vowel sounds corresponding to the seven signs. There is thus no distinction between the qamets gadol and qamets qatan. Every qamets was pronounced with a back short /o/ sound, like saying /ah/ but in the back of your throat and a bit rounded. The IPA sign is this [ɔ].
The complication is that this system does not match what we reconstruct for Biblical era Hebrew based on 1) comparative historical linguistics and 2) Greek transliteration. In that reconstruction, which is similar but not identical to modern Hebrew phonology, the qamets sign represents two different vowels whose qualities reflect different underlying word pattern origins as well as different syllable structures. This leads to the distinction described in the 2nd post in this thread.
Now, the current thread began due to the observation that two different modern recordings of the Hebrew Bible distinguish between the qamets in רָנִּי in Isa 54:1 (pronounced in the recordings with an /a/-vowel) versus רָנִּי in Zeph 3:14 (pronounced in the recordings with a /u/-vowel derivation, the /o/ sound), though both words are written exactly the same. And then two examples of כָל were added -- Prov 35:10 and Prov 19:7. Both examples have the qamets in a syllable structure and stress pattern that normally indicates an underlying /a/ vowel, even though the word in question is always read with some type of /u/-vowel.
On Ps 35:10 and Prov 19:7, note that Gesenius-Kautzsch-Cowley catch this in §9u. They explain it as the /u/-class vowel, the syllable-stress context notwithstanding.
On Isa 54:1, I am co-writing another Baylor commentary on this and so have a great deal of commentaries at hand. No one notes this form as special except to point out that 1QIsaa has רוני. Obviously, this supports a /u/-class vowel underlying the Tiberian qamets.
To answer the question in the post immediately preceding this one: I can only point out errors; I cannot tell you why they made them. A wild guess is that the sequence of three /a/-class vowels, two of which are qamets, in the immediately following word, עֲקָרָה, caught the readers eyes as they scanned ahead (it's necessary to scan a couple words ahead in order to read smoothly, of course) and they misread the first qamets.
That's all I have to say on this matter. It's been a fun thread and I'll be sure to note the issue in our Isaiah commentary.