yes, after i post my problem in this forum i found the bug reporting.
I tried several times to disconnect and riconnect the device but I had no luck. I tried also to shutdown the device and then restart. The glo recognize the books, I read one of them last night. I was waiting for doing some other test before replying in the bug thread
Today I found a thread (italian forum) in which a user had the same problem, after deleting all the tag with a plugin ( i asked what plugin did he spoke of or if he simply removed the tag) he solved the problem.
When I'll go home, i will try to do that kind of test
Sorry for replicating the problem, here and in calibre bug but i thought this forum was just followed by user