Knocks from conversation

Hello. Please help me solve the problem. I recently installed FreePBX Distro, set up, everything seems normal, but there was a problem - sometimes user knocks from conversation and goes to the queue. More detail can be explained as an example: User 109 call 2746646 (toll goes through cisco spa3102, which connected to central telephone 2055048), and ~ at 16:00 user 103 phones rang (with the phone number of the caller is determined as 2746646 passing gateway 2055048, although through this gateway number should not determine, because the operator does not provide callerid), the user 109 at the same time “falls out” of the conversation and hears music. I compared this log with the log of normal passing the call and revealed differences with problematic call. Post the log [] (I divided log into 4 parts (1st [1-106 line] - “#GOOD” - converges with the log normal passing call. 2n [108-277] - “#NOT PROBLEM?” As I understand it, at all not related to the issue, just parallel someone calls. 3rd [279-585] - “#PROBLEM” but where is it? What’s going wrong? 4th [587-597] - continued “#GOOD”. that is, if you cut out second and third parts, the log will be identical to the normal passing call).