grid error

It seems like there is only a single value in fv!row.id. Is there a specific reason why you use merge()?

why do you use apply() and not a!forEach? apply is simply outdated, but i think this looping is not needed in total.

the input for data: parameter -> this lists are the rows you are iterating through
merge() is for combining lists in a specific way. 

in a grid, which already walk through the array of data at the data parameter, you dont need looping usually on top of it.

its kind of way over engineered . fv!row is like "fv!Item" of an "a!forEach" it represent one value of the looped array.

make it easy:

a!gridColumn(

value:concat(index(fv!row,"id",{}),"-",index(fv!row,"exhibit_id",{}))

)