astralsorcery-1.12.2-1.8.2
So between 23 and 24 buckets, chalice can get stuck at 23.8 or 23.9. It will continually absorb more and more liquid from the starwells without ever getting to 24.

Very reproducible, at least for me.

Place two starwells near a chalice. Allow said chalice to fill and manipulate the level in the chalice so that it is an odd decimal, can be done with bucket withdrawals. Soon enough the chalice will get stuck in a loop where it will continually absorb liquid from the starwell without ever filling up to 24, even though it is tantalizingly close to doing so.

Related, but not too bad is that you can forcibly add more liquid to the chalice beyond 24 using buckets. So if chalice is exactly 24, you can add one bucket more to make it 25. If it was 23.x, you can similarly add one more bucket to make it 24.x

So I notice that chalice makes 400 mb withdrawals. At that rate, if it has 23.8, it can not insert 400 since that would put it over 24, though manually bucketing works. So the only way it would stop is if it had 23.6.

Perhaps run the withdrawal code only if it can insert 1000 mb. Thus it would only make 1000 mb withdrawals from starwells that have at least that much and insert into chalice that can accept that much.