Set up the lease to be bi-weekly. Then if she doesn't do that, she is in breach of the lease.

If you don't have that in writing and she stops paying, it will get more complicated when/if you have to evict, since you haven't been following the lease and been allowing a bunch of partial payments as the "norm".

Since the PM get to keep the late fee, there is no downside for them.....and no upside to you......and you deal with the stress if it bothers you.......

If it were me, and the tenant was good in every other way, and I always got the full rent by the end of the month and we could get the bi-weekly IN WRITING, then I would keep going....... if ANY of that doesn't happen, the go.....