Power query losing calculated data after merging queries

How do I troubleshoot the cause of data disappearing after merging two queries? (one of which has been merged with a third query).

The data types are accurate before and after the merge, and there are no null values lurking in the shadows. I've unhidden all columns and carried them over in the merge, in case there was some dependency I don't know about.

The two problem columns have static data from the source table and before the merge there are an expected number of distinct values in each column. After the merge, one column has only 1 distinct value and the second column has twice as many as before the merge.

before:

after:

there are very few applied steps on either query:

this is the join statement:

this is the first query that had a merge of its own, before merging with the salesinput25 query noted above. Is this merge possibly getting in the way somehow?  (it does not have the problem columns, those come from the salesinput file)

i'm really baffled on this and welcome any ideas for how to resolve this.

thanks!

amyfb