I referred the example here to filter out duplicate events. I see that the event id contains = as well as / characters. Are the event id base64 encoded? This is creating issues at times as the document path becomes nested collection if a slash / is found in the id. But to my surprise I was not able to base64 decode them.
For example- 2 id which I could track are - LJ79W2cT0inTJbzFEHH/Aw3i10M= and IQUaGYPQpdYZw3mT3dHRca/Q7tU=.