Without looking at it in depth yet, I’m going to guess because you’re using a match that was cloned from last year is causing issues.
We highly suggest not cloning matches more than 2-3 months out as any updates we make to the website will not transfer over into your cloned match… We have done a tutorial regarding cloning (To Clone or Not to Clone......It's a Question).
Having spots reserved and unreserved in the same squad have caused issues in the past for many matches and many of these matches were cloned too.
I’ll take a look at your match and see if this is the same case you’re having.