Hey @yuning.yan ,
I suspect this could be due to some difference in the event’s client_upload_time and server_upload_time which might be causing this sequence mixup in the event stream. You can read more on those timestamps in here.

Only a Amplitude Platform Specialist would be able to access your org links here to help further investigate if that’s what is causing the issue.

Hope this helps.

Hi @yuning.yan ,

Thank you for writing into the Community! Happy to help. Thank you for the links, I really appreciate it!

From looking at the users, it does seem this is just the path that they take. Looking at the library, I see these events are coming from Segment. So it would be a good idea to contact them and see how they are sending these events for these users, as the timing would suggest the users simply did these events one after the other.

Is there anything that changed in the flow? Was anything added? Have you tried to test the application/website on a Safari 14 ? I do think it is an implementation issue or some browser specific issue. The fact it only happens to Mac users makes me thing it could be an issue with rendering on that specific platform for example. I would try to test the flow of these users and see if there is a way they are being exposed to the last event first and vice versa. 

Have you also been in contact with Segment about this? It would be good to know how they are sending the events exactly and why they differ for these users. What is interesting is looking at this chart it seems to be happening,although not often, on different platforms. Is there any way that a user could do one before the other? Or is there any reason in the code that Segment is sending these early? I would speak with the developers of your team too and see if there is any possibility for someone to complete that sequence instead of the usual flow.

I hope this helps for now! I look forward to your reply!

Kind Regards,
Denis

Hi @Denis Holmes,

Thank you very much for your answer!Your answer provides me with some new problem-solving ideas, but I have a new question.

AS the”OTP Input” fires when user want to login in and click the OTP form to input, and the ”OTP Submitted” fires after user input correct OTP code,users generally cannot complete that sequence instead of the usual flow.We also checked on Segment,and found that this happens when different users log in successively on the same device with short interval. 

May I know how does Amplitude handle the events that happened when different users switch login under the same device?

I look forward to your reply!Thanks in advance!

Hi @yuning.yan ,

Thanks for getting back to me! I did not see @Saish Redkar ‘s answer before and he is also right! Thanks Saish! :D 

From an overview of your account and looking deeper into this, It seems the instrumentation is slightly off. I checked with the device ID from one of the example user: wey1CuVF-HeSMA4bIQ7XfO. There are several users with this device ID, with different user IDs, and the starting event is nearly always ‘OTP submitted’ and there is always user ID assigned to this event, but the strange thing is, after a few events, user ID is gone. We can see this in this chart. We can also see that here. And here. At this moment, I would ask you to speak to your developers and see if there is a reason so many user IDs are tied to just one device ID and also see why the events are being made anonymous half-way through. It would be good to see if you can test out the flow for users a couple of times on different devices and see if this is a common occurrence for the events to be this way. At the minute, it would seem there are higher numbers doing the “incorrect” funnel here than the “correct” one here.

Does this help! I hope this will help with guiding you through troubleshooting the implementation! Let me know if I can help in any other way :)

Kind Regards,
Denis

Hi @Denis Holmes,

Thanks for your reply.

With reference to your opinion, we have further analyzed and tested this issue in the past few days.We found that due to recent activities in our offline store, clerks will help users to register using the public computer in the store,emerged the flow for users a couple of times on the same device.Does Amplitude have a solution to deal with this situation?And I don’t know why are different “device_id” not assigned to different users when they log in with the same device?

I look forward to your reply!Thanks in advance!

Hi @yuning.yan ,

Thanks for the response! Glad you were able to find the root cause. The problem here is that the same device ID is being used for these users when they do not have a User ID, and therefore are merged under the one profile. To combat this, I would first read this article about the manner and then, I would look into which SDK you are using for the website. Let’s say you are using the JS SDK, I would look into this section of the Device ID and I would try to ensure that anonymous users either get an ID in the process(not recommended) or try to set a custom Device ID yourself each time so that they users will not be merged under the one profile. Does that make sense? Let me know if I can help in any other way!

Hi @Denis Holmes,

After reading your reply, I think I know how to solve it.Thank you for your help!

No worries! Glad we could help. If you do need anything from us such as an investigation into a user or something, you can PM me :)