Sniffer packets duplicated or scan twice when sniffing for beacon packets

[MORagab]

Hello everyone , i have noticed that the sniffer can pick up the the packet from the same channel twice.

According to the Bluetooth 4.2 specification, the advertisement should happen on 3 channels in sequence , like what can be seen here for the advertiser part

the setup i used is: one nrf51 dongle as sniffer and sniffing all channels and one nrf51 Development board as beacon advertiser with advertisement interleave of 100ms and advertisement timeout of 1s and the advertisement is repeated 10 time

the sinffer version i used is the latest update 2.0.0-beta3

as can be seen in the figure below the highlighted red box shows that the packets is duplicated during this interval, two packets is picked up from each channel, while if i understand correctly the sniffer should pick up one packet from each channel at each interval like what can be seen in the brown box

is it normal for the sniffer to pick up two packets from one channel or not ? and why ?

also i want to understand how the sniffer hop from one channel to another ? as far as i know is hopping differently than the the normal scanning 

attached the excel file  for the capture packets as i did this experiment 10 times and the capture file from wireshark

https://drive.google.com/open?id=1v4F-s_6yOUMviIBCcn9VLT6m0wSz3fkl

https://drive.google.com/open?id=1WlAbMOu413qPFY7ZxdYONaiaVOfgdUBy

[David Edwin]

I do not see the issue ? can you clarify the issue ? What exactly is the problem.

[MORagab]

i updated the questions a bit , generally the problem is the sniffer sometimes pick up the packet twice from the same channel while the advertising interval is 100ms  

[David Edwin]

Where is the time coming from ? Ideally you should use the delta times in the packet to build the timeline. The timestamp in the packet is a wireshark timestamp being done on the PC and this can be the cause for the issue.