iTunes match is still a mess. The songs are not the problem, aac, 160 kbps, 6 of 7 songs make trouble, song nr. 7 is ok. All from the same album.
Tried everything: delete, re-import, re-match, does not help at all. All troubleshooting tipps provided by apple did not address the problem.
iTunes is not a mature product, it is still beta!!! What a waste of money!
Assuming your network connection is stable it is likely to be an aspect of one or more of these specific Songs causing the issue. An easy route to track the issue is:
1. Create a secure backup of your Songs;
2. Create a playlist of the Songs at issue;
3. Burn the playlist to CD;
4. Delete the Songs & Playlist from the library; restart iTunes & confirm that they are not listed;
5. Set the import from CD parameters to 256 kbit AAC;
6. Sign-out of iTunes Match;
7. Import the Songs into iTunes; restart iTunes & confirm that they are listed;
8. Sign-in to iTunes Match and allow the 3-step process to complete;
9. List Songs with iCloud Status shown.
Provided the Songs have been imported in the correct format they should either be 'matched' or 'uploaded'.