The full solution is below, with a short explanation for each group. To avoid spoilers, play the puzzle or open the hints page before reading the answer panels.
CORTADO, AMERICANO, LATTE, and MOCHA all fit the category "Coffee shop orders". You can hear these at a counter before 9 a.m. The shared link accounts for all four words, which is why the remaining board words should be tested against a different rule.
Category
Computer keys
ENTER / SHIFT / SPACE / ESCAPE
ENTER, SHIFT, SPACE, and ESCAPE all fit the category "Computer keys". They are labeled on many keyboards. The shared link accounts for all four words, which is why the remaining board words should be tested against a different rule.
Category
Kitchen verbs
DICE / FOLD / WHISK / SEAR
DICE, FOLD, WHISK, and SEAR all fit the category "Kitchen verbs". These are actions from a recipe. The shared link accounts for all four words, which is why the remaining board words should be tested against a different rule.
Category
Photo terms
FOCUS / FLASH / LENS / SHUTTER
FOCUS, FLASH, LENS, and SHUTTER all fit the category "Photo terms". A camera owner knows these. The shared link accounts for all four words, which is why the remaining board words should be tested against a different rule.