My understanding is that this provision was originally enacted by Republicans during Trump's first term, so it follows Trump's practice of fixing things he was the one to break in the first place and attempting to claim credit.
Then why didn't the Democrats fix it when they were in power?
It is slightly worse than that. The provision was changed by Republicans… but set to kick in after Trump’s first term, so the negative effects landed on Biden. Now that Trump’s back in office, it’s safe to improve the economy again without the wrong party getting credit for it.