Hey

I am doing an upsert of a source DataFrame into a target table. Before said upsert, I print out the source DataFrame's row count, which is a bit smaller than what `numSourceRows` says after the operation completes and I check the operationMetrics. Two things occurred to me as to why this is happening:

• The matching condition is being matched more than once (it's not, I checked. And it wouldn't make sense that this affects the field, according to what the Doc says)
• Some rows are being modified because they are written in the same page as the other truly modified rows (still doesn't make sense).

What situations might cause this?