OS? Version of InDesign?
I can't say I've seen any difference in text selection with smart guides enabled.
It happens that way in Illustrator as well.
Learn the shortcut: Cmd-U on Mac, or Ctrl-U in Windows toggles Smart Guides on and off.
Sometimes you want it turned on, sometimes turned off.
This has been an issue for me spanning many versions and Mac OSs. I am currently experiencing the issue with version 2015.3 on El Capitan.
I think the best solution to-date is to toggle Smart Guides with Cmd-U, but it would be great to make text selection completely independent from any form of snapping in future releases.
Also turn off Snap to Guide: View > Grids & Guides > uncheck "Snap to Guides". That's Shift+Cmd+; on Mac or Shift+Ctrl+; in Windows.