The reality is, however, that publishing is changing very fast, and to keep up with that pace, publishers are moving quickly to get their books into stores like Amazon and iBooks. That’s great, I want as much content available as possible. But I also demand, and believe that all readers should demand, the high quality that book publishers have always offered to their customers.
As the above article points out, ebooks are typo-ridden.
Major publishers are at fault, as well as indies. When an authors' backlist is published, the print copy is converted to digital text via OCR (Optical Character Recognition). There are always errors.
Proofread your ebooks, then upload. If you find errors, publish a new, corrected version. Your readers will appreciate it.