Understanding Classic Rewards release availability

[SYD]

I was just using the standard flight search, not the multi city. I get different results each time. On rare occasions I get those CR seats (only twice so far).
The problem is I get locked up unable to move the dates around, need to restart the search and those CR seats are gone from the next search.

The trick with MC search is make sure you check the "Flexible with dates for all flights" check box. On the calendar view, if you see a day with flights, but on selecting that date, it's not suitable eg something like SYD-DFW-SCL, click on "Dates" to get back to the Calendar view and keep scrolling through the calendar. If you've moved on a few weeks past the initial search date, redo the search from that last date (to save scrolling again through 14 day chunks).

Also, if you do click through on seats and get to the payment page, there's a good chance those seats will be locked out of other searches waiting for you to purchase them. If you don't, they should eventually come back.

Anyway, I couldn't see anything CRs over in May/June but there are still some seats on 30 Jul and a couple of days in Aug. Coming back there were some options.

What's also really annoying is it won't let me mix 'n match a paid sector with a CR. eg there are two seats SCL-SYD on 4 June but I can't book that with a cash fare SYD-SCL... That's usually possible...