Important update (initial post was made by my company account): Even I tested this problem again (without subdomain) it works perfectly. But at work I used subdomains for different multisite installations (because of reasons). After a new test at home with subdomain, I wasn’t able to edit textfields. So, this problem is only on multisite wordpress installations which are running on subdomains. Now, this is a very specific problem and I will perhaps use different domains instead of splitting up in different subdomains… but maybe you can look for a solution, this would be great!
