Help! - Multiple events for the same transaction?

I am new to Snowplow, so forgive me if this is a simple question, but I’m analyzing our atomic events data, and I’m seeing multiple instances of some transactions (as defined by me as having the same tr_orderid, tr_total, and domain_userid with event_name=‘transaction’). Here are some characteristics of these transactions:

  1. Event_id’s are different for all 3 transactions
  2. The events were tagged with 3 different domain_sessionids
  3. The events occurred successive days (11/4, 11/5, and 11/6)
  4. The events all came from different user_ipaddresses but from the same network (first 2 sets of IPv4 values are consistent).

I’m probably missing something, but don’t know for sure what. The customer was working from an Android mobile device, and we are not collecting any structured events. Any help would be greatly appreciated.

Thanks!
Adam Knust