PTF 8.55 Issue - PTF failing to input into required field when running a script

I'm am currently experiencing a strange issue and I do not know what's going on.

We are currently going through a PeopleTools upgrade (from 8.54.32 to 8.55.19).

In my test environment, the tools upgrade was successful, and I ran the script upgrade utility, which successfully upgraded all the scripts.

BUT, whenever I run a script, it occasionally misses the User ID field (or sometimes the password field) when logging in (or sometimes another the script misses another field randomly if it actually logs in).

The Execution Options are set up correctly, and I can see in the Message Tool that PTF is actually trying to put the username into the User ID field but it just simply fails to do so.