This approach does not appear to be able to handle when the first event is not "yes":
| makeresults
| eval data="Col_A=\"ID_A\",Col_B=\"log 0\",Col_C=\"no\";Col_A=\"ID_A\",Col_B=\"log 1\",Col_C=\"yes\";Col_A=\"ID_A\",Col_B=\"log 2\",Col_C=\"no\";Col_A=\"ID_A\",Col_B=\"log 3\",Col_C=\"yes\";Col_A=\"ID_C\",Col_B=\"log 5\",Col_C=\"yes\";"
| makemv data delim=";"
| mvexpand data
| rename data as _raw
| KV
| table Col_A, Col_B, Col_C
| stats count as eventCount first(Col_C) as startsWith list(Col_B) as Col_B list(Col_C) as Col_C by Col_A
| search startsWith="yes"
| table Col* eventCount
I added a log 0 event to the data and ID_A disappeared:
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