Solution: Unfortunately, it is not possible to offer a universal filling method that works equally well on all systems. For this reason, such problems can occur. However, you can solve them as follows:
Go to Options -> Passwords -> Default auto-complete method and try one of the other methods. One will work in any case.
If you do not want to change the auto-complete method for a specific reason, go to Options -> Actions -> Auto-complete and try to adjust the delay value until auto-complete works correctly.
HINT: For the default auto-complete method to be applied from the options, you must ensure that the entry in question uses the Use global settings value which can be found under Properties -> Additional -> Auto-complete method.