I've enabled "Delete blocked cookies". However, some "blocked" cookies are not deleted; instead, uMatrix tries to delete non-existing cookies.

Used versions: uMatrix 0.9.3.2, Firefox 38.6.0 (iceweasel) on Linux

Details / Steps to reproduce:

1. Remove all cookies (Firefox -> Edit -> Preferences -> Privacy -> Show cookies... -> Remove all)
2. Enable uMatrix-log
3. Open some sites, here: ebay.de, ebay.com, youtube.com, google.de.
   All these sites set cookies.
4. Look which cookies exist. Here, only cookies from ebay.de, ebay.com, youtube.com, google.de exist.
   (Firefox -> Edit -> Preferences -> Privacy -> Show cookies...)
5. Wait about 2-3 minutes.
6. Now, the youtube.com-cookie is gone, but the ebay.de-/ebay.com-/google.de-cookies are still there.
7. Look into the uMatrix-log. It says:
   • "cookie deleted: http://youtube.com/..." (OK)
   • cookies for ebay.de, ebay.com, google.de are not deleted (bug)
   • And I get a whole bunch of "cookie deleted"-messages for non-existing cookies / for cookies which existed a few hours ago, e.g. "cookie deleted: https://twitter.com/..." (I've been on twitter some hours ago.) (bug)
8. Wait some more (e.g. 10 minutes) -- no "cookie deleted" messages occur in the log.
9. Open youtube.com -- a new cookie is set.
10. Up to 2 minutes later, the youtube-cookie is correctly deleted ("cookie deleted: http://youtube.com/...").
11. 2 minutes after the "cookie deleted: http://youtube.com/..." entry, a whole bunch of additional "cookied deleted:"-messages of non-existing cookies occur in the log (but of other domains than at point 6; twitter.com is not listed, but others which were not listed at point 6, are).

This looks like the cookie-tracking in uMatrix is broken: It does not correctly track existing cookies, but thinks that there are cookies, which do not exist.