Text Add Tool Reversed
i was adding text to a PDF via the Add Text tool. it suddenly started to type backwards and across the page with large gaps between the letters. i restarted my computer and the problem persisted in the same file. i did nothing to change the settings when this happened--it was 100% spontaneous. i had no way to undo this bug and i had to create a new document to get it to stop.
Grace Sifuentes commented
This is the solution for Adobe Acrobat Pro 2017, so you can try it on the software you're using.
When editing a document, the Format tool to the right has a box that shows AV and an arrow underneath it. If the number in that box is not zero, change it to zero. This fixed my problem! I stumbled on the solution, but I hope it helps others.