Is there an explicit end-of-period event for Rush Soccer (eFootball)?

The rush soccer feed currently has no explicit period-end signal. The PERIOD_CHANGE event is emitted when the second half starts, and that is the only indication that the first half has ended. The end of the second half is visible only when the match status changes to FINISHED. So the inference you described is the intended behaviour today. We may consider exposing the match phase directly on the current map state (first half, added time, half time, second half, ended) in the future so you do not have to reconstruct it from events. However, there is no promise or ETA for the time being. Until then, you should keep using PERIOD_CHANGE for the first half and FINISHED match status for the second.