have been wrestling with "proficiency-based" instruction for quite awhile now.
It's not new. It's a recycling of the old, failed, "Mastery Learning/Outcome Based Education" reforms from the 1980s. Some of us are old enough to remember, lol.
Before SB2200, we were already dealing with this; the law just put more teeth into it.
Here's a consequence I've dealt with the last several years:
Students who do nothing all term long and try to give me an entire term's worth of "evidence" the day before report cards are due...whole bunches of them, which means that the end of the term is a nightmare.
We're adjusting to the demands of a "proficiency-based" system. We recognize that students are also supposed to be learning non-academic skills before we send them out into the world as adults:
responsibility; organization; work/study habits...
I never did include those in an academic grade. They go in the "citizenship" grade. That still appears on the report card, so we aren't grading "exclusively on academic mastery." At least, on our report card. I can't speak for the whole state.
Homework? Everything I assign, including homework, has at least one required standard attached. They have to demonstrate mastery of that standard. When they don't do the assignment, it doesn't demonstrate mastery. It shows up as an "incomplete."
We send home regular progress reports that show what we are working on, what is "proficient," what is "incomplete," etc.. No student is going to reach the end of the term without having done the work to learn and demonstrate that learning unless parents are compliant in their slacking.