Given
'''<translate> test</translate>'''
When rendered with the legacy parser, "test" is in bold. When rendered with Parsoid, we get
<p data-parsoid='{"dsr":[0,34,0,0]}'><meta typeof="mw:Annotation/translate" data-parsoid='{"dsr":[3,14,null,null],"wasMoved":true}' data-mw='{"rangeId":"mwa0","extendedRange":true,"wtOffsets":[3,14]}'/><b data-parsoid='{"autoInsertedEnd":true,"dsr":[0,14,3,0]}'></b> test<meta typeof="mw:Annotation/translate/End" data-parsoid='{"dsr":[19,31,null,null]}' data-mw='{"wtOffsets":[19,31]}'/><b data-parsoid='{"autoInsertedEnd":true,"dsr":[31,34,3,0]}'></b></p>
and "test" is not in bold.
Considering the behaviour without the <translate> tag (not in bold), it can be argued that the parsoid behaviour is the correct one here.
This is visible from the rt-testing on https://meta.wikimedia.org/wiki/Tech/News/2014/02 between bc2040ce and 89070d9e.