Datepicker doesn't use theme color after update to 4.2.6

Hi, today I finally started to update my websites to 4.2.6, being extremely careful after all these reported issues that the last versions were obviously causing (I stayed on 4.2.3 until today but needed the Instagram widget to work on some sites). I updated via FTP deleting the previous Enfold folder. On each single website I updated today I stumbled into different problems, but I could solve them all as they seemed to be caching issues or whatever. However the most difficult update of Enfold in a long time. Never mind ;-).

One thing I couldn’t solve: the datepicker in the contact form does not accept the individual theme color setting anymore but now seems to be what I would call the Enfold standard theme, which means green buttons instead of the the theme color. I assume something went wrong in an updated file that is calling the colors of the datepicker? Any idea how to fix this? Oh and yes, of course I disabled all plugins to check if one of them is causing the issue, they are not, not even WP Rocket. Example page in private content.

Thanks a lot for your help, cheers!