Sorry about that. We'll be sure to file this behavior into our system to hopefully be addressed in a future release. In the meantime, we can use some custom script to fix the problem. Assuming your grid question is row-oriented, please try adding this script to it:
<script>
$(document).ready(function(){
// Settings
var inputLabels = [
'alpha',
'beta',
'gamma',
'delta',
'epsilon'
];
// Run
$('input[name="hid_row_list_[% QuestionName() %]"]').val().split(',').forEach((row, index) => {
$('#[% QuestionName() %]_div .mobile_grid_card:nth-child(' + (index + 1) + ') .grid_cell_text').text(inputLabels[row - 1]);
});
})
</script>
Lines 5-9 are where we need to put the input labels for each row of the question. You can copy-and-paste and update these to meet your needs.