Please help, Xiaobaitu, on questions of I-94 when visiting Canad

Just saw your comment on Sept 09: "去加拿大没有问题，因为不收I-94"

Two further related questions:
1. Is a new I-94 issued when this person re-enters USA?

2. How risky is that one is going to visit Canada (like for a meeting)before receiving the receipt of I-485 application? Will this I-485 be considered automatically abandoned by USCIS?

MANY MANY thanks!