Select multiple answer is cleared if itemset is used and more than one choice is selected

[lognaturel]

Software versions

JavaRosa v2.15.0

Problem description

When a select multiple is dynamically generated, it is impossible to select multiple choices because the answer gets cleared.

See https://forum.opendatakit.org/t/problem-with-select-multiple-with-odk-collect-v1-23-1-and-v1-23-0/21242 for sample form and reproduction steps.