Dataview query for modified files over seven days

What I’m trying to do

I have a Dataview query on my daily journal page which displays the files which have been created or modified on that day.

Both queries work on journal pages running back to seven days, but after that the modified files query stops.

Is this a limitation of dataview or am I doing something wrong?

WHERE file.mday =
SORT asc  

Things I have tried

Google around for alternative ways to code this.