Hi @zhangsh,
Thanks for reaching out and welcome to the forum.
Would you please send the full document for these transactions? Please redact any personal information that might exist on these documents.
Also, are you using any type of proxy or load balancer for APM server?
As a side note, the current version of the RUM agent is 4.4.2. we recommend to use the latest version since we have made many improvements since version 3.0.0.
Cheers,
Hamid