add different custom fields value to post class if permalink or index

ok have a working fix, I used an if else statement combined with is_home to change

<article id="post-<?php the_ID(); ?>" <?php post_class(get_field('custom_field_X')); ?>

to

<?php if ( is_home()) post_class(get_field('custom_field_X')); 
else post_class(get_field('custom_field_Y')); ?>>

which has removed the custom_field_x settings from the permalink pages fo the posts.

maybe there is a more elegant solution out there but from my current knowledge this is the best I could do