Yes, time machine missing backup folders/files has been asked before and gone unaswered. I can't touch those threads as a new, reputationless member. It's very dissapointing to discover missing folders and files from full time machine backups.
I look forward to answers on this. This is by far one of the most disappointing feeling about Apple and a well recommended way of backing up.
Imac(21.5-inch, Mid 2011)
Processor 2.5 Ghz Intel Core i5
Memory 8GB 1333 DDR3
Mac OS 10.7.5
Folder missing folders and files:
/Users/[user]/Library/Application Support/
Best Answer
It is a nasty bug of OSX 10.9 and 10.10 . Some workaround is described here: Time Machine is skipping files and folders. How to fix? by Pete.
... I see you are running 10.7.5. So maybe Apple ruined Time Machine already with Lion. I personally never had the issue with 10.6.8, then directly upgraded to 10.9 and then later discovered missing files in my backups. So you can confirm if the above workaround also helps with OSX 10.7.5 Lion.