The Hindi script in 'reading Mode' are abnormally faulty , the proper way of each letters are misleading in manner while switching to reading mode.
Please make sure to the letters to be on exactly same as the original docs while switching to reading mode. Or may provide proper hindi fonts.
Are you observing the issue with all your files? Could you please explain the issue in detail at firstname.lastname@example.org and share problematic PDFs so that we may help you better? Thanks, Adobe Acrobat Team