2
You can try any or all of the suggestions
in this thread.I don't yet use 2.4.5 so the registration process files may have changed a little.
To be honest, I was hoping the human Vs robot registration issue would have been addressed in the core by now using a protection layer below the captcha.
Something needs to be done as a lot of users seem to suffer from this problem.
A thread is for life. Not just for Christmas.