Experiencing the same problem but, only with wordpress with Qtranslate-X activated. (ACF Pro or Qtranslate-X deactivated, the problem disapear). Roled back ACF to 5.8.2 is the solution for now.
I have the same problem on my site, unable to switch between Visual and Text buttons since ACF 5.7.0.
For me, problem seen only on frontend form ( acf_form() ).
I have also the same Wp version 4.9.7