What about prematurate optimism?
If you look at the OOB, you'll notice that the M-307 is available from 2007 to 2020 as AGL unit (unit class #7, unit #182), along with more credible Mk-19 AGLs. However, in the formations list, the AGL platoon (formation #061) is available ony until December 2002 for some reason. I think the bug is more likely here. Why would the Israelis stop using
all of their AGLs in 2002?
Since you can only
buy formations, there is no formation available after 2002 in which you could buy AGLs, be them Mk-19s or OCSWs. But in the campaign, once you are allowed to change a unit (which you can also do while building a scenario, but not in a battle) you can switch any unit (say a HMG section) to the forlorn AGL section.
So an OCSW in the Israeli OOB is probably only wishful thinking done some years ago, but the fact that no AGL is available after 2002 looks more like a typo or a baseless OOB quirk, unless someone can back it up with some data.