How long does it take for her to get down to the boat dock from where she was parked? I suppose she could have been anxious to see this person, so she kept dialing the number. Once she approached the boat dock area, she may have seen this person or his (or her) vehicle and quit dialing. If this was someone she had just recently met, this person may have given her a false number knowing he / she was going to commit this crime.
Other things that seem strange to me. . . .
1. She was known as an avid "text" user . . . so why the short message to the boyfriend?
2. Given the fact she was a teen, and known to text a lot, I cannot imagine she would have been meeting someone and her friends did not know. If it was spur of the moment, I'd think phone records would help LE there. If planned, someone should know unless she lacked close friends or was very private.
I have other thoughts / questions, but my brain is fried. More later . . . thanks for reading.
IIRC, it's maybe 5 mins or less to the boat dock..Supposedly the family that claims not to know MC has a son who works with MC's boyfriend but I still like your 'false #' theory ..It is strange the text to boyfriend is so short & this has been discussed numerous xs over the many months now since she was murdered.