Awww, I hate this time of year,

RE: The Cambridge dictionary would appear to disagree!

No, it agrees. That's a standard dictionary entry for verb forms: base form, past simple, past participle.

Past simple and past participle are not interchangeable. Compare: see, saw, seen or go, went , gone. Standard forms are "I have seen" and "I have gone". Ditto "I have written".

Non-standard forms are everywhere of course. Very common in Yorkshire speak: "That's wot wer wrote darn!"