When using Amplitude Analytics, "000" is added at the end of our session IDs, confusingly

Hello all 😄

I wanted to raise a question regarding session IDs and their use in Amplitude Analytics.

We have found (through searching for specific session IDs in Amplitude Analytics) that Amplitude adds on an extra three zeroes to our existing session IDs, which initially caused some confusion while searching for said IDs.

For an example: we may have a session ID of “1234567891” that we pass into Amplitude. When we then search for this in Amplitude Analytics, we find that this session ID can now be found as “1234567891000”

I wanted to raise this to understand whether this intentional or whether this was potentially a bug?

Thank you for any responses!