Outgoing call log shows calls from my own number to the same number

Question

Every so often, I pick up the phone to dial out and get a fast busy tone.  I hang up, wait a few seconds, and try again, and I have dial tone and can dial out.
I have not noticed any pattern or timeframes when this occurs.
When looking at my online call log, I see calls at very random and arbitrary times of the day in the Outgoing column from my own number and TO the same number.  ALWAYS after that there is an entry that the call went to voice mail.  There is never an actual voice mail message, of course; I guess it hangs up before VM detects a valid message.
There appears to be an entry like this every single day, but, again, at very different times and with no discernible pattern.
Why is my own phone number trying to dial out to itself and at various times of day and night? 

Answer 1

Having the same issue. Calls being made FROM my Maryland home landline TO a Virginia number.
I tried calling the number from my office phone, but it goes straight to an unoccupied voicemail.
When I first called about it, the Verizon representative also reassured me there was no charge for these calls, but that is not the issue. The issue is that someone or some machine has access to my home landline and it is making these calls. She was pretty insistent that it must be someone in my home, but much like others have stated, the records show that calls are made when no one is home, or when we are all home watching TV in the living room. We have one phone in the kitchen, so there are no secret calls being made. And certainly not 20+ times a month.
The first representative transferred me to another tech. At first, the new tech dismissed the idea that there could be cross-wiring (what the first tech suggested) because it's over the internet. There are no physical wires to cross.
The tech eventually ran a test and determined there was a "short bound in the wiring," so she said she was going to "reboot the ONC." I don't know what any of that means.
The test came back successful, and she was able to block the number (inbound and outbound).
I told both techs that this problem is not unique to my account; that there are several people on Verizon forums reporting the same issue.
She was not able to explain why, so we are no closer to figuring this out.
All I can recommend is calling Verizon tech support and having the number blocked. We'll see what happens with the next bill.
Also, if it's worth typing out, make sure you're reviewing your bills from Verizon. I've had to call at least five times in the 4.5 months about one thing or another.