I have an odd problem merging two files based on state variables, called est_st. In both data sets, there are 51 values of est_st, for each of the 50 states and DC. All observations are complete in each data set and there are no other values. I have them both converted to byte variables with %8.0g.
But when I try to merge m:1, the states WA, WI, WV and WY don't merge and and some new values of est_st are created with values like 3, 14, etc.
My code is
merge m:1 est_st using pres2020medexpand.dta

Any clue as to why my data aren't merging correctly?