Warning while using asiSelectInst

I'm developing a form which at a certain point needs to allow the user to select an instance from their schematic. I then need to fetch the database object of that instance to do some further processing. I'm using asiSelectInst for this, in the following callback from a button on my form:

(procedure selectDUT(field scope)

    (sevOpenSchematic (axlGetToolSession sess testname))

    (asiSelectInst 'mydutfield ?prompt "select instance..." ?form myform ?tab (list 'mytabs 'page1))

)

"mydutfield" is an uneditable string field. I gave it a callback which fetches the database instance, so whenever asiSelectInst changes the value of the field, the callback is initiated:

(procedure fetchDUTInst(field scope)

    (let

        (

            (cv (geGetEditCellView))

            inst

        )

        (setq inst (car (exists obj cv->instances (equal obj->name (car (last (parseString scope->mydutfield->value "/")))))))

         ...

    )

)

This works like a charm....almost. Sometimes, when I open the form for the first time, asiSelectInst fails with the following warning, printed to the CIW:

*Warning* No window and/or doneProc argument passed to
"astiSelectInst", selection not started

The value in mydutfield doesn't change, and the callback is not executed. If I immediately try again, it works no problem, and continues to work all subsequent times. I've not been able to determine the exact conditions under which it fails, but it always seems to be when the form/maestro view is first opened.

Am I doing something wrong here?

I'm on version IC23.1-64b