Yes it is,
because of same mistake (hopefully?) in /administrator/views/config/tmpl/default_priceconfig.php
if($this->shopgrp_price) echo '<tr><td colspan="2">'.vmText::sprintf('COM_VM_PRICEDISPLAY_CONFIGURED_BY SHOPPERGRPS',implode(',',$this->shopgrp_price)).'</td></tr>';
In this case the real constant consider here is only the bold part "COM_VM_PRICEDISPLAY_CONFIGURED_BY SHOPPERGRPS" and this one is unique, so it works.
That's why I have a space at the beginning of the sentence in admin, because of the unused constant part with the space in it.