Combined dataflow - most rows missing

Hello,

I am combining 9 dataflows into one dataflow. When doing so I lose most of the source rows. So for example, a source table as verified in PBI works and gives multiple millions rows of data. But the same table returns just a few tens of thousand rows in the combined dataflow. I use the gen 1 dataflow.

What could cause this? I think the total is around 40 million rows, and the combined dataflow refresh time is 1h 30 min which is less I think than the cap of 2 hours.

I have tried to look into datatypes, and the main field existing in all tables, like part number and location seem to be the same, (but I haven't verified the data type of all included fields from all source tables.) So not sure what is going on.

I have thought I could try to create a new dataflow and add one dataflow at a time and verify the result in PBI after each pass, but it is a lot of work. The filtering being made in the combined dataflow is simple, it is removing columns and filtering on part number which shouldn't have this effect on the number of rows at all.

Thanks for any help in order to track down the cause of this discrepancy. I have Googled and used AI to try to solve it but so far I haven't solved it.

// Daniel