Tolkien wrote several times that Orcs don't like the light. That doesn't mean they never went into it but it does indicate that some might not go into the light unless forced. You don't know Tolkien's work as well as you think if you believe it doesn't fit with what he wrote on the subject.
Thus because of the curse that lay upon them the Noldor achieved nothing, while Morgoth hesitated, and the dread of light was new and strong upon the Orcs…East rode the knights of Dol Amroth driving the enemy before them: troll-men and Variags and orcs that hated the sunlight….‘Unless our enemies rest also, they will leave us far behind, if we stay to sleep.’ said Legolas. ‘Surely even Orcs must pause on the march?’ said Gimli. ‘Seldom will Orcs journey in the open under the sun. yet these have done so,’ said Legolas. ‘Certainly they will not rest by night.’‘Now straight on!’ shouted Uglúk. ‘West and a little north. Follow Lugdush.’
‘But what are we going to do at sunrise?’ said some of the Northerners.
‘Go on running,’ said Uglúk. ‘What do you think? Sit on the grass and wait for the Whiteskins to join the picnic?’
‘But we can’t run in the sunlight.’
‘You’ll run with me behind you,’ said Uglúk. ‘Run! Or you’ll never see your beloved holes again. By the White Hand! What’s the use of sending out mountain-maggots on a trip, only half trained. Run, curse you! Run while night lasts!'