I work PACU and BLS, ACLS, and PALS are required, they were not upon hire, but were before orientation was completed and we are required to keep re-certified. Our hospital keeps track of all of our dates and has a page that we log into each quarter to do necessary training and updates, we can see if or certifications are due.
let me make sure I understand this. You did not know you needed to keep current in PALS, it was 7 days past due, you took the day off to recert and got paid for it, and upon arrival back had your recertification but still had to sign form stating you know if it ever lapses again you'll be placed on unpaid leave or fired.
If there are no other problems with your manager, I would not worry about this. No harm, no foul, keep it updated in the future. Sometimes managers are just following the rules outlined maybe because it's not in the policy book, but now you've signed you can be held accountable.... maybe it was what needed to be done in order to be paid for that day.
But if your manager has had other complaints about you, and/or you've had to visit HR more then once, sign written notices or similar, then I'd be looking for a new job. Managers that start reporting everything to HR are compiling a record for a reason, to justify disciplinary actions or termination.