I found a regex that crashes sublime consistently when run under “Find in Folder” but works perfectly during normal find in file searches.
(class|id)="(\w+)(^\s]+)*"
(class|id)="(\w+)(^\s]+)+" also causes the crash.
Update: it appears that the problem was with using a + in a matching group that executes + or * times.
(class|id)="(\w+)_(^\s])*" works fine for both find in folder and find in file searches.