Rotate PDF Pages only re-applies a page's rotation when the requested angle differs from the page's current rotation attribute, otherwise it keeps the page as loaded.
Adobe's support community explains that using the View > Rotate View menu only changes the on-screen display temporarily, while the separate page-rotation tool changes the saved file. Adobe PDF will not save rotated pages, why? | Community
Rotate PDF PagesPdf Still Sideways After Rotating
Add the sideways file to the page before picking a new angle.
Select the target angle for the specific pages that appear sideways.
Download the processed PDF file from the results screen.
Verifying Saved Rotation Attributes
Open the downloaded PDF in a separate viewer application.
Check the page orientation against the requested angle.
Continue with Combine Multiple Files or Rotate in 90 Degree Increments.
Frequently Asked Questions about Fix PDF Still Sideways After Rotating
How do I rotate a PDF page permanently?
Avoid the browser's own view-rotate shortcut and use the site's rotation buttons instead.
Where do I find the rotation option?
Look for the rotate icons beside each page thumbnail.
How do I verify the rotation worked?
Compare the page's orientation in two different PDF viewers.
What should I do if the page still looks sideways?
Repeat the rotation and confirm the correct direction before downloading again.