Looks like Alfresco (Community 201707) have some trouble with searchable word selection into OCRed pdf files?
See some shift of selection, not really under the real words and letters. Its unusable if need select and copy/paste some word from OCR pdf.
Its a bug (please confirm somebody) or can be tuned for normal look?
On picture also Chrome and Adobe Reader window with same file and normal selection directly under letters. So its looks like not OCR engine problem but Alfresco rendering.