Yosemite consolidating multiple desktops on dual monitors,

I have a Mac mini (mid 2010) - 2.4 GHz - 350 GB - Yosemite 10.10.2 - with dual LG monitors. Instead of using Mission Control I prefer to have multiple desktops on each monitor. I dedicate a single app to each desktop, e.g., Safari, iTunes & iPhoto on Mon1 facing Mail, Messages & Calendar on Mon2, and swipe between apps, which I find more convenient. Six numbered desktops plus Dashboard.

In Mavericks this arrangement was preserved on restart. However, in Yosemite, all apps on Mon2 are consolidated in a single desktop, the remaining 2 desktops - 4 & 5 - have migrated blank to Mon1, PLUS an additional blank desktop - 6 - is generated on Mon1. The single desktop on Mon2 is now 7. On subsequent restarts there become eight, then nine, then ten desktops, etc.

I've been up and down the settings options, tried System Help, outside searches, and even mentioned the issue in passing during an unrelated Apple Tech Support call. To no avail. I had hoped that one of the updates would resolve this. It is easily but inconveniently resolved manually, but as I mentioned this was a non issue in Mavericks.

I mentioned this problem in an earlier post, but in less detail. Has anyone else experienced or heard of this?