This is so bizarre, I wonder if anyone else has found it true.
Since probably version 2.6 of WP, the auto upgrade feature for plugins has been VERY erratic for me. I'm talking about on 20+ WP installs on that many domains, hosted on VPS accounts with 2 different hosting companies.
I've tried all the fixes, suggestions, etc., here and just spent a couple of days with my current web host support, trying to figure out why some plugins will auto upgrade and some won't. It's been true since 2.6 right up through 2.8.1.
I discovered with some persistence just last week that just about every plugin which fails to auto upgrade -- that means MOST of them in my cases -- will almost always auto upgrade on the 3rd try.
Sounds almost spooky, I know. The three which NEVER auto upgrade first time are Google XL Sitemap, All-in-One-SEO pack, and the Ozh Drop Down Menu plugins. (I've even contacted Ozh via email and he's told me the plugin never fails to auto upgrade for him. Go figure.)
On those three and any others, if I get failures to copy files, failures to remove old files, etc., all the stuff I usually get when they fail to auto upgrade -- they always auto upgrade on the 3rd try.
Thoughts? Suggestions? Others seeing this?