Why is the segmentation is not filtering the data properly?
Background:
We have a session ID that concatenates ECID+ a data layer variable + Date & Timestamp: 23605613089604234583067550836421046746|0|2023|9:20 26
When checking the data we are seeing some inconsistencies:
1) Half of the data is not pulling in the ECID -

2) Some data is pulled into the data with the data - element name

3) the remaining half of the data looks correct.
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Now for my question
When I create a segment [Visitor container] - and filter using "Does not Start with" - It still shows me data starting with what I am trying to filter out.
The opposite is also true when I try to segment the data by "Starts with" - It shows me data


As you can see the data is not being segmented correctly. I have checked by using "HIT" level container but the idea behind the session ID is that its for visitors.
Any advice would be useful here.